Role of Ultrasound Elastography in Patient Selection for Prostatic Artery Embolization

Clinical question
Is baseline ultrasound elastography predictive of prostate artery embolization efficacy?

Take away point
Baseline prostatic elastic modulus and shear wave velocity measurements each predict efficacy of prostate artery embolization at 1 year.

Reference
de Assis A.M., Moreira A.M., Carnevale F.C., Marcelino A.S.Z., Antunes A.A., Srougi M., and Cerri G.G. Role of Ultrasound Elastography in Patient Selection for Prostatic Artery Embolization. J Vasc Interv Radiol. 2021 Oct; 32 (10): 1410-1416.

Click here for abstract

Study design
Prospective, observational, descriptive, single-center cohort study.

Funding Source
No reported funding

Setting
Academic setting. University of Sao Paulo Medical School, Sao Paulo, Brazil.

Figure

Figure Scatter plots showing a moderate positive correlation between baseline SWV and 12-month IPSS (R = 0.68, P = .002) (a) and EM and 12-month IPSS (R = 0.62, P = .007) (b). EM = elastic modulus, IPSS = International Prostate Symptom Score (IPSS < 8, optimal; IPSS ≥ 8, suboptimal), SWV = shear wave velocity.

Summary

Ultrasound elastography (US-E) has recently been described as a novel tool to evaluate prostate artery embolization (PAE) outcomes with anatomical and functional assessments in patients with benign prostatic hyperplasia (BPH). US-E demonstrated that PAE not only treats bladder outlet obstruction (BOO) by reducing prostate volume, but also by improving the α-adrenergic mediated effect on prostatic muscular tonus, which addresses the dynamic component of BOO. While recent US-E research gave interesting insights on PAE mechanism of action, research on the prognostic role of US-E is lacking.

The authors performed a prospective, observational, descriptive, single-center cohort study involving 20 consecutive patients. Inclusion criteria were lower urinary tract symptoms LUTS) attributed to BPH for at least 6 months refractory to standard medical treatment (α-1 adrenergic receptor antagonist with or without 5-α reductase inhibitor), international prostate symptom score (IPSS) ≥ 8, and prostate volume ≥ 40 cm3 and ≤ 200 cm3. Exclusion criteria were biopsy-confirmed cancer, active urinary infection, presence of urinary retention requiring use of Foley urinary catheter, serum creatinine ≥ 2 mg/dL, and previous pelvic surgery or radiotherapy. From February 2018 to October 2019, 20 patients met inclusion criteria but 2 did not return for follow up and 1 refused to complete evaluation therefore the remaining 17 entered statistical analysis.

Primary endpoints were prostatic elastic modulus (EM) and shear wave velocity (SWV) assessed with US-E up to 30 days before and at 23–37 days after PAE. Patients on α-1 adrenergic antagonist were maintained until after the second US-E evaluation, after which the medication was permanently withdrawn. Secondary endpoints included IPSS questionnaire, IPSS-Quality of Life (QoL) item, and peak urinary flow rate (Qmax) assessed using uroflowmetry, among others. All ultrasound examinations were performed transrectally with an 11C3 endocavity probe (Toshiba Medical Systems Corporation, Otawara, Japan) on a Toshiba Aplio i800 (Toshiba Medical Systems Corporation) utilizing 2-dimensional sound wave elastography (SWE) via acoustic structure quantification and dynamic energy generation via acoustic radiation force impulse that generated multifocal stress and enabled EM and SWV measurement by building colored elastographic maps. This meant the exams did not depend on tissue compression by the operator during examinations. EM and SWV values were obtained from maps including the transitional zone of both lobes of the prostate simultaneously in at least 2 axial slices at the middle third of the prostate. All examinations were performed by the same radiologist (A.S.Z.M.).

Pearson product-moment correlation tests were used to assess association of IPSS at 1 year with baseline EM and SWV. Receiver operating characteristic (ROC) curves were used to determine predictive cutoff values of baseline EM and SWV. PAE efficacy at 1 year was considered optimal at IPSS < 8, QoL < 2, or Qmax ≥ 12 mL/s, respectively. Area under ROC curves were obtained at 95% confidence interval and statistical significance was defined as bicaudal type I error (p) < 0.05.

16 of the 17 patients (94.1%) underwent bilateral PAE. Catheterization was technically unsuccessful in the remaining 1 patient (5.9%) due to atherosclerosis. EM was moderately positively correlated with IPSS at 1 year (R = 0.62) and SWV was slightly more positively correlated with IPSS at 1 year (R =0.68), with both correlations being statistically significant (p = 0.007 and p = 0.002, respectively). SWV was also slightly positively correlated with QoL at 1 year but without statistical significance (p = 0.09, R = 0.41). Baseline EM ≥ 50.14 kPa predicted suboptimal IPSS with 84.6% specificity, suboptimal QoL with 68.8% specificity, and suboptimal Qmax with 80.0% specificity; and baseline SWV ≥ 5.9 m/s predicted suboptimal IPSS with 100% specificity, suboptimal QoL with 81.3% specificity, and suboptimal Qmax with 90.0% specificity. Results consistently demonstrated inferior PAE outcomes for patients with very low initial prostate elasticity, with potential to predict patient suitability for PAE using the possible prognostic cutoff values of EM < 50.14 kPa and/or SWV < 5.9 m/s.

Commentary

This study (1) further described PAE’s effect on prostate elasticity as measured via EM and SWV, and (2) explored the prognostic value of US-E in categorizing patients as good candidates for PAE by assessing IPSS, QoL, and Qmax at 1 year. A notable advantage to this study was the use of ultrasound that utilized dynamic energy generation via acoustic radiation force impulse, which meant ultrasound exams were not operator dependent. 

Possible limitations include the fact that all ultrasounds were read by the same radiologist, who is one of the authors and no indication of blinding was described, and the sample size of 17. 

This research further supports the hypothesis that PAE’s efficacy is based, at least partially, on prostate elasticity, which is a dynamic component to BOO. The results suggest a potential prognostic role for US-E in patient stratification for PAE. Additional future study, perhaps multi-center and/or with blinding, can be helpful in continuing to explore these initial promising results.

Additional Reading:

Video presentation on the history and development of shear wave elastography: https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11242/112420B/Shear-wave-elastography--from-ultrasound-to-optics/10.1117/12.2540509.full?SSO=1

Review on acoustic radiation force impulse imaging: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337770/

Post Author
Zayn Mohamed, JD
MS-4 Doctor of Medicine Candidate,
University of South Florida Morsani College of Medicine

Edited and formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Modified Microcoil for Preoperative Localization of Solitary Pulmonary Nodules: A Prospective, Single-Arm, Multicenter Clinical Study

Clinical Question:
What is the efficacy and safety of the modified microcoil device for use in precise preoperative localization of solitary pulmonary nodules (SPNs) prior to video-assisted thorascopic surgery (VATS)?

Take Away Point:
Image-guided percutaneous placement of the modified microcoil device can facilitate efficient thorascopic resection of SPNs.

Reference:
Modified Microcoil for Preoperative Localization of Solitary Pulmonary Nodules: A Prospective, Single-arm, Multicenter Clinical Study. Zhang, Zhiyuan, et al. Journal of Vascular and Interventional Radiology. 2021; 32: 1470-1477. doi.org/10.1016/j.jvir.2021.06.026.

Click here for abstract

Study Design:
Prospective, single-arm, multicenter clinical study.

Funding Source:
Beijing Municipal Science & Technology Commission, Capital Funds for Health Improvement and Research, and Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support.

Setting:
Three (3) Institutions; (1) Beijing Friendship Hospital, Capital Medical University, China. (2) The First Affiliated Hospital of Bengbu Medical College, Bengbu, China. (3) Nantong Tumor Hospital, Nantong, China.

Summary:

Video-assisted thorascopic surgery (VATS) is a minimally invasive option for malignant lung tumor removal. However, a large percentage of solitary pulmonary nodules (SPNs) are not localized or palpated during VATS, particularly non-solid/semisolid nodules, of which up to 78% have been reported to contain malignancy. Localization of SPNs prior to surgery can significantly improve VATS success rate. Several techniques are currently utilized to localize pulmonary lesions before excision, including both liquid markers and solid metallic markers/hooks.


A new modified microcoil device (designed in collaboration with Cherish Medical Device; Jiangsu, China) was prospectively evaluated as a method to enhance preoperative SPN coil localization. The device (Figure 1) involves partial insertion of the microcoil within the lung parenchyma, with its tail placed above the visceral pleura (Figure 2).


The prospective, multi-center study included 96 consecutive patients (96 PMNs) from 3 medical centers who underwent CT-guided SPN localization. Inclusion criteria included patients aged 18-75 years with peripheral lung nodules (diameter ≤ 2cm). Patients were excluded if they were deemed unsuitable secondary to clinical limitations, severe systemic disease, organ failure, or coagulation disorders.

Primary outcomes were measured as both technical and clinical success. (1) Technical success was defined as microcoil deployment within 10 mm of lesion edge and (2) Clinical success was defined as successful microcoil positioning with visual confirmation during VATS, lack of microcoil dislodgement or displacement, and maintained coil integrity during excision. Secondary outcomes were safety, including complications during deployment and any adverse device-related events.

Technical success rate was 100% and clinical success rate was 96.9% (95% CI, 91%-99%); all 96 nodules were successfully resected during VATS. Microcoil dislodgement occurred in 3 patients, likely due to nodule proximity to the visceral pleura. The complication rate was 1% with  asymptomatic pneumothorax not requiring intervention (minor complication) incurred in 1 patient and no major complications otherwise. All nodules were resected. No major complications or cancer recurrences were observed 90 days following excision.

Commentary:

The authors conclude that the new modified microcoil device is safe and effective for SPN localization prior to VATS, with a reported localization success rate of 96.9% and SPN resection rate of 100%, without the need for fluoroscopy.

Specifically, the authors highlight features of the microcoil device including a helical tail to clearly mark the pleural surface without the need for fluoroscopy, a push rod with marking scale allowing rapid and accurate deployment, and microcoils of various lengths to compensate for SPN location variability.

Techniques for pulmonary nodule needle localizations have been previously described and typically involve wire-localization with the modified hook needle technique (e.g. Kopans, Hawkins) and/or methylene blue staining. However these techniques could only be utilized in the immediate pre-procedural setting. This device allowed for much more flexibility in the timing of surgical excision (e.g. following-day VATS) while maintaining a very low complication rate.

The reported results illustrating the safety and effectiveness of the new modified microcoil device are promising. However, the study was not without its limitations. Learning curve was not evaluated. Only patients with solitary lung nodule were included in the study. And most importantly, there was no comparison group and therefore the comparative benefits of this device and its associated technique could not be evaluated. Large-scale, randomized clinical trials are needed to determine whether the modified microcoil has advantages over other devices such as conventional microcoils and hook wires

Additional Ref:
Thistlethwaite, P. A., Gower, J. R., Hernandez, M., Zhang, Y., Picel, A. C., & Roberts, A. C. (2018). Needle localization of small pulmonary nodules: Lessons learned. The Journal of Thoracic and Cardiovascular Surgery, 155(5), 2140–2147. https://doi.org/10.1016/j.jtcvs.2018.01.007

Post Author:
Noam Kupfer, MD (PGY-3)
Vascular & Interventional Radiology (Integrated) Residency, Class of 2025
Rush University Medical Center

David M. Tabriz, MD
Assistant Professor - Vascular & Interventional Radiology
Program Director - Vascular & Interventional Radiology (Integrated) Residency
Program Director - Vascular & Interventional Radiology (Independent) Residency
Rush University Medical Center
@DrDaveTabriz

Edited and formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Percutaneous MR Imaging-Guided Laser Ablation and Cryoablation for the Treatment of Pediatric and Adult Symptomatic Peripheral Soft Tissue Vascular Anomalies

Clinical question
Is magnetic resonance (MR) imaging-guided laser ablation, cryoablation safe and effective in treating symptomatic soft tissue vascular anomalies (VAs) in the trunk and extremities?

Take-away point
MR imaging-guided laser ablation and cryoablation are both safe and effective in treating symptomatic soft tissue VAs in the trunk and extremities.

Reference
Augustine MR, Thompson SM, Powell GM, et al. Percutaneous MR imaging-guided laser ablation and cryoablation for the treatment of pediatric and adult symptomatic peripheral soft tissue vascular anomalies. Journal of Vascular and Interventional Radiology. 2021;32(10):1417-1424.

Click here for abstract

Study design
Retrospective cohort study

Funding source
Self-funded or unfunded

Setting
Single institution, Mayo Clinic Rochester, MN

Figure

Figure 1. Magnetic resonance (MR) imaging-guided laser ablation in an 8-year-old female patient with persistent pain from a right lateral thigh intramuscular slow flow venous malformation after multiple prior percutaneous sclerotherapy treatments. (a) The T2-weighted preablation MR image showed a hyperintense intramuscular slow flow venous malformation in the right lateral thigh (yellow arrow). (b) Intraprocedural T2-weighted MR imaging showed the laser fiber (yellow arrow) traversing the venous malformation. The venous malformation was ablated with multiple pullback activations of the laser fiber. After ablation, (c) the T2-weighted and (d) T1-weighted gadolinium-enhanced images showed a decreased T2 signal and enhancement throughout the venous malformation (yellow arrows).

Summary

Soft tissue vascular anomalies (VAs), also referred to as vascular tumors, can result in significant symptomatology whether benign or malignant, simple or combined. These symptoms can be localized, such as pain and cosmetic issues, as well as systemic and life-threatening such as high-output heart failure or consumptive coagulopathy. These masses have classically been treated with surgical resection, percutaneous sclerotherapy, or transarterial embolization depending on characteristics such as size, location, proximity to critical structures, and flow. These modalities often have variable success, requiring multiple treatments to attain remission. Percutaneous ablation procedures, including radiofrequency (RF), cryoablation, and laser ablation, have been demonstrated to be safe and effective in treating the more refractory VAs. However, the most-commonly employed imaging modalities, ultrasound and computed tomography (CT), are limited in their abilities to visualize vascular lesions. Magnetic resonance (MR) imaging is a promising alternative given its unmatched ability in delineating soft-tissue boundaries and its demonstrated ability to effectively monitor treatment response in VAs.

In this retrospective case series, patients with symptomatic VAs treated with MR-guided laser ablation or cryoablation over an approximately 6-year period were analyzed. Patients were included if they had persistently and locally symptomatic VAs after previous first-line therapies, were not offered further first-line therapies, and had lesions in locations that were deemed safe for ablation procedures. All patients underwent pre-procedural MRI and had their pain assessed on the visual analog scale (VAS). Post-procedurally, patients followed up 6-12 months later to have their pain reassessed. This was done via VAS, and patients were classified as either having complete, partial, or no resolution of symptoms. Post-ablation MRI was only obtained if patients had residual symptoms, which occurred in 17 patients. Pre- and post-ablation MR images were compared in terms of maximum VA diameter of the T2 hyperintense portion, semiquantitative percentage enhancement of the total VA at baseline, and the percentage decrease in the T2 signal and enhancement at follow-up. Major and minor complications were also analyzed.

30 patients with 34 VAs treated over 60 sessions were included in this study. The VAs were located in the thorax (n = 3), abdomen/pelvis (n = 2), upper arm (n = 5), forearm (n = 1), hand (n = 1), thigh/hip (n = 12), and lower leg (n = 10). 31 VAs in 27 of the patients caused moderate to severe pain and 3 VAs in 3 patients caused swelling/mass effect, prompting treatment. Mean baseline pain score in painful VAs was 6.4 ± 1.6. 9 patients were taking analgesics to manage this pain, including 2 taking narcotics, 2 taking both narcotic and non-narcotic medications, and 4 patients taking neuromodulatory medications. All 34 VAs were classified as low-flow malformations. Of the 60 ablation procedures, 49 were done with laser, 10 with cryoablation, and 1 with both. The median number of ablations per VA was 1.5 (1-7). 27 ablations utilized both US and MR guidance while 33 used MR alone. Laser ablation was the default modality choice while cryoablation was used in cases in cases with nearby critical structures. 18 sessions resulted in same-day discharge, 36 resulted in overnight observation, and 6 were admitted for greater than 24 hours. All 6 admissions were for post-ablation pain control. Only 23 patients with 27 VAs had adequate follow-up data. At a mean of 12.2 months ± 10.1 (0.4-29.3), 19 (95%) of patients treated for pain and 2 (67%) of patients treated for swelling/mass effect reported partial or complete resolution of symptoms. Mean pain score was 1.6 ± 1.8 (0-5) with a mean reduction of 5.7 ± 1.0 (p < 0.001). 17 patients underwent post-ablation MRI. 15 of these were with contrast. Reduction in maximum size from baseline was 2.3 cm ± 2.7 (p = 0.004). 13 patients experienced >50% decrease VA T2 signal while 11 patients experienced >50% decrease in VA contrast enhancement. No major complications were noted. 10 minor complications occurred in 9 (30%) of the patients. These included post-ablation hematoma (n = 3), transient paresthesia (n = 4), transient weakness (n = 2), and nontarget thermal injury (n = 1).

Commentary

This study builds off of smaller studies of its kind and reports promising outcomes in a larger patient population. MR imaging-guided laser and cryoablation are shown to be safe and effective modalities for treating symptomatic peripheral VAs, both as initial and subsequent therapy for persistent lesions. MR guidance specifically helps to visualize and treat VAs that were not conspicuous on US or CT imaging. Patients suffering from painful lesions in particular experienced significant decreases or resolution in pain post-procedurally. All complications were minor and were treated with minimal observation or short-term hospitalization. 

This study has several limitations, including its retrospective nature, difficulty in accurately measuring VA dimensions post-ablation, and lack of consistent pre-procedure workup and post-procedure follow-up. Also, the use of subjective pain scores is subjective and highly variable. Lastly, the included number of patients/ablations was inadequate to allow detailed assessment of the differences between cryo-ablation versus laser ablation, nor location-specific VA response. Future studies would benefit from symptom reporting standardization, prospective randomized design, and larger patient population.

Post Author
Jared Edwards, MD
General Medical Officer
Medical Readiness Division
Naval Surface Forces Pacific, San Diego, CA
@JaredRayEdwards

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Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Yttrium-90 Radioembolization to the Prostate Gland: Proof of Concept in a Canine Model and Clinical Translation

Clinical question
To investigate the feasibility, safety, and absorbed-dose distribution of prostatic artery radioembolization (RE) in a canine model

Take-away point
Prostate Y90 RE is safe and feasible in a canine model, with focal dose-dependent prostate changes, without unwanted extraprostatic effects.

Reference
Mouli SK, et al. Yttrium-90 Radioembolization to the Prostate Gland: Proof of Concept in a Canine Model and Clinical Translation. J Vasc Interv Radiol. 2021 Aug;32(8):1103-1112.e12.

Study Design
Preclinical animal study

Funding Source
Research grants from Boston Scientific provided to Northwestern University Department of Radiology, Section of Interventional Radiology.

Setting
Single-center.

Summary

Prostate cancer is the most common non-cutaneous cancer in men. Currently, nonoperative candidates are managed with brachytherapy (BT) or external-beam radiotherapy (EBRT), however biochemical recurrence and radiation induced toxicity to adjacent structures range from 10% to 60%. Prostatic artery (PA) embolization already has an established safety and efficacy profile for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH). However, both bland and chemoembolization for prostate cancer have not shown efficacious outcomes in small studies. Y90 radioembolization has proven efficacy and safety as HCC locoregional therapy and may be replicated for prostate cancer treatment.

14 castrated canines were assigned to Y90 treatment groups: low (60-70Gy), medium (80-120Gy), and high dose (150-200Gy). Doses were delivered to 1 hemi-gland of each subject. After 60 days, gross pathologic and histologic analysis of the prostate, bladder, penis, rectum, urethra, and the left and right neurovascular bundles was performed.

Y90 administration was technically successful in all subjects, with dose delivered to target hemigland without significant non-target exposure by imaging. Serial MRI follow up demonstrated hemigland volume significantly and progressively decreased with noticeable signal changes on T2 weighted, ADC map, and DCE (dynamic contrast enhanced imaging) sequences. The high-dose group demonstrated higher volume loss (60%) compared to the low-dose group.

Gross pathological examination demonstrated radiation-induced glandular changes in a dose-dependent fashion, with the high-dose group demonstrating increased degeneration, inflammation, and atrophy of the prostatic gland sand glandular epithelial metaplasia. The majority of the contralateral control hemiglands were histologically unremarkable. No adverse events were noted on clinical, pathologic, or histologic analysis including: cavitary necrosis, hemorrhage, urinary retention, incontinence, hematuria, diarrhea, or rectal bleeding. No significant radioactivity was detected in the animals’ urine and feces during follow up. No gross pathological or histological abnormalities were seen in the surrounding tissues upon necropsy including perianal inflammation or necrosis, urethral strictures, radiation cystitis or proctitis. In 1 high-dose subject, there were isolated microspheres in the periprostatic tissues (bladder, rectum, neurovascular bundle) but no evidence of tissue damage. Particularly, the neurovascular bundle (NVB) appears to be relatively spared in radioembolization.

Commentary

The authors noted that EBRT or brachytherapy have better homogeneity, but at the expense of more normal tissue exposure. The beta particle penetration of Y90 has limited range which provides more accurate locoregional target tissue coverage with limited risk to surrounding structures. Even with high theoretical absorbed doses delivered to the treated prostate hemigland (155–502 Gy), the most conservative QUANTEC limits were not exceeded for surrounding organs.

Some drawbacks noted during this study were that each animal served as its own control with the contralateral untreated prostate hemigland, which may have received some inadvertent dose due to intraprostatic collaterals. Furthermore, compared to similar canine models for prostate bland embolization, the volume changes with radioembolization in this study were not as profound and were dose dependent. However, the level of atrophy was still greater than those seen following EBRT in preclinical and clinical studies. The author also noted a few limitations of the study, namely (1) a canine prostatic hyperplasia model was used and (2) microdosimetry provided a range of dose distributions from ideal to conservative due to limitations gland segmentation on micro-CT.

This study proves the technical success of Y90 prostate radioembolization in a canine hyperplasia model, demonstrating pathologic and histologic evidence of significant dose-dependent glandular atrophy without evidence of radiation induced side effects. Perhaps most notably, neurovascular bundle sparring is an attractive opportunity if similar treatment effects can be proven. This is a very promising first step and we look forward to the ensuing clinical safety and efficacy trials.

Post Author
Vaishak Amblee, MD
Rush University Medical Center
Integrated Vascular & Interventional Radiology Residency, Class of 2023

David M. Tabriz, MD
Program Director, Vascular & Interventional Radiology (Integrated)Program Director, Vascular & Interventional Radiology (Independent)
Rush University Medical Center
@DrDaveTabriz

Edited and formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Combined Transarterial Embolization and Percutaneous Sclerotherapy as Treatment for Refractory and Nonresectable Aneurysmal Bone Cysts

Clinical question
To evaluate the use of combined transarterial embolization (TAE) and percutaneous sclerotherapy in the treatment of nonresectable and refractory aneurysmal bone cysts (ABCs).

 
Take away point
Combined TAE and percutaneous sclerotherapy is a minimally invasive, safe, and effective procedure that can be used to treat nonresectable ABCs and to significantly improve patients’ quality of life.

Reference
Masthoff M, Gerwing M, Schneider KN, et al. Combined Transarterial Embolization and Percutaneous Sclerotherapy as Treatment for Refractory and Nonresectable Aneurysmal Bone Cysts. J Vasc Interv Radiol. 2021;32(10):1425-1434.e2. doi:10.1016/j.jvir.2021.07.008

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Study design
Retrospective, single-center, observational study that included patients with refractory and nonresectable ABCs treated with combined TAE and percutaneous sclerotherapy. Decision to treat with combined selective TAE and percutaneous sclerotherapy was made by an interdisciplinary board.

Funding Source
No reported funding.

Setting
Academic setting. University Hospital Münster, Münster, Germany; University Hospital Essen, Essan, Germany; University Hospital Ludwig Maximilian University of Munich, Munich, Germany.

Figure



Flow scheme of the treatment algorithm for combined transarterial embolization and percutaneous sclerotherapy for refractory and nonresectable ABCs.

(a) and (b) Representative images of transarterial embolization of an aneurysmal bone cyst (ABC) of the left clavicle. Angiography showed arterial hypervascularization of an ABC (a, black arrowheads) with arterial feeding vessels from the axillary artery. Superselective embolization of the feeding vessels led to the complete embolization of the ABC, while the axillary artery was successfully spared. (c) Representative fluoroscopic imaging of percutaneous sclerotherapy after transarterial embolization followed by administration of the sclerosing agent via the percutaneous bone access needle (white asterisk). (d) Baseline T2 axial magnetic resonance (MR) imaging showed the typical appearance of an ABC (white arrowhead) with T2 hyperintense, partially blood-filled cysts. (e) Follow-up T2 axial MR imaging scan after treatment showed a heavily reduced number and size of cysts (white arrowhead) with complete mineralization of the ABC. (f) Baseline radiograph showed the typical osteolytic, multicystic appearance of an ABC of the left clavicle. (g) Follow-up radiograph showed complete mineralization of the ABC after combined transarterial embolization and percutaneous sclerotherapy.

Summary

ABCs are rare osseous lesions that tend to occur in people under the age of 20. Symptoms may include pain, swelling, neurologic symptoms due to local nerve compression, movement restriction, or pathologic fractures. The goal of ABC therapy is to eradicate neoplastic tissue and enable remineralization. The mainstay treatment has been complete intralesional curettage or excision and filling. Alternatives including TAE, percutaneous sclerotherapy, or denosumab therapy have also been used.

The authors preformed a retrospective review of 16 consecutive patients who were treated with combined TAE and percutaneous sclerotherapy for refractory and nonresectable ABCs. Median age of the patients was 17 years. Only 1 of the patients had a history of pathologic fracture at the initial presentation. Seven of the patients had not undergone any previous therapies for ABC, one had a prior curettage, and none had undergone any systemic therapies. Data collected by the investigators included radiographic and magnetic resonance (MR) imaging, in addition to quality-of-life assessments which were performed prior to the first and at least 4 weeks after the final intervention. The median follow-up was 27.3 months. Two radiologists who were blinded to the interventions independently assessed the imaging data for several variables: number of intralesional cysts, size of the largest cyst, occurrence of pathologic fractures, grade of intralesional mineralization (using a 5-point Likert scale), and grade of lesion fluid-fluid levels (using a 4-point Likert scale established in the literature). TAE and percutaneous sclerotherapy treatment sessions were performed sequentially. TAE was used to achieve complete arterial devascularization and percutaneous sclerotherapy followed TAE until either ABC necrosis was achieved (using diminished lesional contrast enhancement as a marker) or clinical symptom relief was attained.

The interventional procedures were performed under general anesthesia. Feeding vessels of the ABCs were embolized using EVOH (Onyx Liquid Embolic System). During the same session, multiple percutaneous accesses into a majority of the ABC cavities were achieved under fluoroscopic guidance. Sclerotherapy was performed by injecting DiscoGel, which contained gelified 96% ethyl alcohol, cellulose derivative product, and tungsten and polidocanol. The investigators used 2 standardized outcome parameters, the Musculoskeletal Tumor Society (MSTS) score and the 36-Item Short Form Survey (SF-36), to assess clinical outcome and quality of life. For both these parameters, higher scores represent a higher quality of life.

Clinical Outcome – Imaging Data

Overall, a mean of 1.6 ± 0.7 TAEs and 3.2 ± 1.7 percutaneous sclerotherapies were performed with a technical success rate of 100%. Complete or subtotal, defined as >90% of arterial feeding vessels, was achieved in all patients. No adverse events were reported during the procedures and no procedure-associated long-term adverse events were observed at follow-up. Follow-up imaging scans showed a decreased number of intralesional cysts in 15/16 patients and a decreased cyst size in 14/16 patients. ABC lesion mineralization significantly increased while the fluid-fluid levels of the ABCs significantly decreased (P < .0001). All 9 patients who received contrast-enhanced follow-up MR imaging showed either complete (1) or partial response (8) to treatment. There was also a significant reduction in mean contrast-enhanced lesion size following therapy (P = .0003). There was no pathologic fracture development during the follow-up period and no patient had ABC recurrence after the initial treatment response. One patient became a surgical candidate after intervention led to ABC downstaging, and one patient was switched to denosumab therapy after showing prolonged partial response.

Clinical Outcome – Quality of Life

Both scoring systems, the MSTS score and the SF-36 survey, showed significantly improved quality of life scores. The MSTS score increased to 28.8 ± 1.8 from a baseline of 14.1 ± 8.6 (P < .0001). Similarly, the SF-36 physical functioning score improved from 44.3 ± 32.3 to 93 ± 13.5 (P <.0001) while the SF-36 score for role limitations due to physical health improved from 23.3 ± 40.6 to 93.3 ± 25.8 (P < .0001). Only 1 patient did not demonstrate significant improvement in both SF-36 categories. The SF-36 also assesses the effects of physical disease on mental health; all mental health-associated categories demonstrated significant improvement (P < .001). Social functioning (P = .0004), pain (P < .0001), and outlook on future health (P < .0001) all significantly improved. Overall, the MSTS and SF-36 scores demonstrated a clinical success rate of 93.8% in improved quality of life.

Commentary

The authors of this study demonstrated the efficacy and safety of combined TAE and percutaneous sclerotherapy for the treatment of refractory and nonresectable ABCs. The similar success rate of this minimally-invasive intervention to primary surgery may warrant further investigation into using combined TAE and percutaneous sclerotherapy in new contexts; either as primary treatment in resectable ABCs or to downstage lesions to facilitate future surgery. Additionally, the lack of ABC recurrence during the median follow up of 27.3 months demonstrates the superior durability of this method compared to other treatment strategies. There are several limitations to this study, including but not limited to its retrospective nature, the lack of control group, heterogenous distribution of ABC lesions, lack of standardized response criteria for bone lesions, and failure to perform contrast-enhanced follow-up MR imaging on each patient. In spite of these limitations, this study is important because adds credence to the idea that the pathogenesis of ABCs stems from dysplastic vessels and neoplastic cell proliferation. Current treatment options for ABCs tend to favor a surgical approach; however, applying the treatment strategies in this study to a wider range of ABC patients, initially in a prospective trial setting for clinical validation, may improve overall clinical outcomes.

Post Author
Kaelan Chan
Medical Student, MS4
University of Cincinnati College of Medicine

Edited and Formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

PÉRDIDA DE SANGRE PERIOPERATORIA EN PACIENTES CON EMBOLIZACION PREVIA DE LAS ARTERIAS PROSTATICAS BILATERALES, SOMETIDOS A PROSTATECTOMÍA SIMPLE: ANALISIS DE PAREAMIENTO POR PUNTAJE DE PROPENSIÓN

Pregunta clinica
¿Es la embolización bilateral de las arterias prostáticas (EBAP) segura y eficaz para reducir la pérdida de sangre intraoperatoria durante la prostatectomía simple?

Mensaje principal
La embolización bilateral de las arterias prostáticas preoperatoria reduce de forma segura y eficaz el sangrado intraoperatorio y el tiempo quirúrgico.

Reference

Sare A, Kothari P, Cieslak JA, et al. Perioperative blood loss after preoperative prostatic artery embolization in patients undergoing simple prostatectomy: a propensity score‒matched study. Journal of Vascular and Interventional Radiology. 2021; 32(8):1113-1118.

Click here for abstract

RESUMEN

Proposito

Evaluar la pérdida de sangre perioperatoria después de la embolización bilateral de las arterias prostáticas (EBAP) antes de la cirugía en pacientes sometidos a prostatectomía simple.

Métodos
Se hizó una revisión retrospectiva de las historias clínicas identificando 63 pacientes (edad promedio, 65.3 ± 8.0 años) con hipertrofia prostática benigna y síntomas graves del tracto urinario inferior, que se sometieron a prostatectomía desde septiembre de 2014 a diciembre de 2019. Dieciocho pacientes (28.5%) fueron sometidos a EBAP antes de la cirugía. Se obtuvieron datos demográficos, resultados de laboratorio, información del procedimiento operatorio, detalles del curso hospitalario e informes de patología. Se realizó un análisis de pareamiento por puntaje de propensión 2: 1 para comparar la pérdida de sangre intraoperatoria en los pacientes que se sometieron a prostatectomía simple, con la pérdida de sangre intraoperatoria en aquellos que se sometieron a EBAP antes de la cirugía.

Resultados
Dieciséis (89%) de 18 pacientes fueron sometidos a EBAP antes de la cirugía. Treinta y dos pacientes que se sometieron a prostatectomía sin embolización antes de la cirugía fueron seleccionados para el análisis de pareamiento por puntaje de propensión 2: 1 basado en la edad, raza, tipo de cirugía, tamaño de la glándula prostática y comorbilidades. La pérdida de sangre estimada (PSE) promedio para la prostatectomía simple fue de 545 ± 380 ml (promedio ± desviación estándar). Hubo una reducción estadísticamente significativa en la PSE en los pacientes que se sometieron a EBAP (303 ± 227 ml, p <0.01). El tiempo operatorio también se redujo significativamente en los pacientes que se sometieron a EBAP antes de la cirugía (p <0,05). Los pacientes que se sometieron a EBAP no presentaron complicaciones relacionadas con el procedimiento.

Conclusiones
La EBAP antes de la cirugía parece ser segura y puede ser eficaz para reducir el sangrado perioperatorio y el tiempo operatorio.

Resumen

La hiperplasia prostática benigna (HPB) es una causa común de síntomas del tracto urinario inferior, afecto a la mayoría de los hombres mayores de 60 años y a más del 80% de los hombres mayores de 70 años. El tratamiento de primera línea ha implicado históricamente modificaciones en el estilo de vida y uso de farmacoterapias con inhibidores de la 5 α-reductasa, bloqueadores α, e inhibidores de la fosfodiesterasa; recomendándose la cirugía si estas medidas no proporcionan un alivio adecuado. Las opciones quirúrgicas incluyen resección transuretral de la próstata (RTUP) y prostatectomía simple abierta, con tasas de complicaciones que aumentan a medida que aumenta el tamaño de la próstata. La complicación más común es el sangrado que requiere transfusión, y se ha demostrado que ocurre en 11.9% de los pacientes sometidos a prostatectomia simple abierta, que generalmente se realiza en pacientes con próstatas grandes. Se ha demostrado que la embolización preoperatoria es un método seguro y eficaz para reducir la pérdida estimada de sangre, las transfusiones y la duración de la estancia hospitalaria (EH) durante la resección de una variedad de tumores hipervasculares, pero aún no se ha evaluado en pacientes sometidos a prostatectomía.

En esta serie retrospectiva de casos, se analizaron 63 pacientes con hipertrofia prostática y con síntomas obstructivos del tracto urinario bajo (SOTUB). Todos los pacientes tenían próstatas con peso mayor de 80 gramos y posteriormente se sometieron a prostatectomía. Los pacientes se sometieron a EBAP o no embolización antes del procedimiento. Se excluyeron los pacientes sometidos a EAP unilateral. Los datos recopilados incluyeron la información demográfica, las comorbilidades, el volumen prostático preoperatorio (obtenido con ultrasonido transrectal), tipo de prostatectomía, detalles técnicos de la EBAP, laboratorios hematológicos pre y postoperatorios, PSE, tiempo operatorio, transfusiones y la duración del postoperatorio con irrigación continúa de la vejiga (ICV). En los pacientes sometidos a embolización se practicó una EBAP utilizando microesferas de hidrogel de 250 μm hasta el cese del flujo anterógrado, seguido de una inyección de gelfoam. Dentro de las 2 semanas posteriores a la EBAP los pacientes se sometieron a una prostatectomía robótica o a una prostatectomía abierta suprapúbica.

En este estudio se analizaron 60 pacientes, 16 pacientes sometidos a EBAP y 44 pacientes que no se embolizaron. De los 44 pacientes no embolizados, se incluyeron 32 para el pareamiento por puntaje de propensión en relación 2:1. En el grupo de embolización, 11 pacientes se sometieron a prostatectomía robótica, mientras que 5 se sometieron a prostatectomía suprapúbica abierta; en comparación con 10 y 22 pacientes respectivamente en el grupo sin embolización. Las características demográficas y basales entre los grupos no fueron significativamente diferentes. La mediana de tiempo entre EBAP y prostatectomía fue de 6 días (4-18 días). La PES promedio fue de 303 ± 219.7 ml en el grupo de EBAP en comparación con 545 ± 380 ml en el grupo no embolizado (p < 0.01). El tiempo operatorio promedio en el grupo de EBAP fue de 140.5 ± 35.4 minutos frente a 180.5 ± 56.6 minutos en el grupo no embolizado (p < 0.01). La disminución en la hemoglobina durante la cirugía fue de 2.16 g/dl en el grupo de EBAP y de 3.50 g/dl en el grupo sin embolización (p = 0.020). El 6% de los pacientes del grupo EBAP se sometieron a transfusión en comparación con el 19% en el grupo sin embolización, pero con una promedia de 0.19 unidades por paciente en el grupo EBAP versus 0.44 en el grupo sin embolización, que no fue significativamente diferente (p = 0.334). La EH no difirió significativamente entre los grupos y no se produjeron complicaciones mayores o menores.

Comentario

La Asociacion Americana de Urologia recomienda la cirugía como estándar en atención de la HPB; sin embargo, las próstatas grandes pueden ser difíciles de tratar y tienen tasas más altas de complicaciones hemorrágicas. La embolización de las arterias prostáticas ha demostrado que es segura y eficaz para el tratamiento de la hematuria relacionada con la próstata y los SOTUB. Este estudio demostró una disminución en la pérdida de sangre operatoria y en el tiempo promedio operatorio en pacientes sometidos a EBAP preoperatoria antes de prostatectomía para próstatas grandes (> 80 g). Sin embargo, no demostró una reducción estadísticamente significativa en la EH o en el uso de transfusiones. La falta de diferencia en las transfusiones puede deberse al tamaño reducido de la muestra en combinación con variabilidad en los umbrales de transfusión entre los urólogos. El único estudio previo similar a este, y que se menciona en este estudio, encontró una disminución en la EH y pérdida de sangre intraoperatoria, pero solo se usó como referencia la variación en los laboratorio hematológicos y no evaluó las PES. Esto sugiere que la falta de La diferencia significativa en la EH en este estudio puede deberse al tamaño de la muestra. Esta es una reconocida limitación del estudio además de su naturaleza retrospectiva. Un desafío en La estandarización propuesta por los autores es el intervalo de tiempo relativamente grande entre EBAP y prostatectomía, que puede haber resultado en diferencias en el desarrollo de circulación colateral antes de la cirugía, lo que resulta en diferencias clínicamente significativas en la pérdida de sangre. Las futuras investigaciones deben centrarse en ensayos aleatorizados que incluyan múltiples centros con gran volumen de procedimientos y en investigaciones sobre el tiempo en el desarrollo de la generación de circulación colateral en la próstata.

Autor del comentario
Jared Edwards, MD
Oficial Medico General
Division de Preparación Médica
Fuerza Navales de Superficie del Pacifico. San Diego, CA
@JaredRayEdwards

Translated by Pilar Bayano Molano, MD
Associate Professor Interventional Radiology
UT Southwestern Medical Center

Formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Safety and Efficacy of Peripheral Embolization with EASYX Liquid Embolic Agent: A Multicenter Prospective Study

Clinical question
Is EASYX, a new non-adhesive precipitating liquid embolic agent based on a polyvinyl alcohol ether polymer labeled with iodine molecules, safe and effective for peripheral embolization.

Take away point
EASYX is a novel copolymer liquid embolic agent that is safe and effective for peripheral embolization. The absence of tantalum allowed reduced CT artifacts on imaging follow-up, which was especially useful in patients with type II endoleaks.

Reference
Sapoval M., Vidal V., Dean C., Del Giudice C., Tradi F., Chevallier O., Charles-Nelson A., Pellerin O., Loffroy. Safety and Efficacy of Peripheral Embolization with EASYX Liquid Embolic Agent: A Multicenter Prospective Study. J Vasc Interv Radiol. 2021 Aug; 32 (8): 1136-1143

Click here for abstract

Study design
Prospective, observational analysis of embolization using EASYX on a range of indications including varicoceles, type II endoleaks, portal vein embolization before hepatectomy (PVE), acute arterial hemorrhage, and angiomyolipomas (AML).

Funding Source
The study was funded by a grant from Antia Therapeutics and Qmedics. The study was sponsored by Assistance Publique-Hôpitaux de Paris.

Setting
Academic setting. AP-HP - Hopital Europeen Georges-Pompidou Paris, France, Paris, Ile-de-France, France

Figure

Figure. Cone-beam computed tomography of the gonadal vein after previous coil embolization and re-embolization with EASYX. The gonadal vein was 100% occluded and because EASYX contains no tantalum, no beam artifacts were seen, comparing favorably to the artifact around the metallic coils that had been previously implanted.

Summary

EASYX liquid embolic is a new liquid embolic rendered radiopaque by iodine bound to the polymer backbone, thus minimizing beam-hardening artifacts on follow-up imaging associated with liquid embolics containing micronized tantalum as the radiopaque agent. Research of EASYX in a porcine model reported effective embolization without safety/technical issues; however, studies using humans have not been reported. The authors performed a multicenter, prospective, open label phase 2 study at 3 centers in France to assess the safety and efficacy of EASYX use in humans with a range of indications. A total of 8 interventional radiologists used the device for the study purpose, and embolization was performed according to the SIR guidelines for percutaneous transcatheter embolization for each indication. Statistical analysis used quantitative variables expressed as mean ± SD and range, and qualitative variables expressed as raw numbers (n) and proportion and percentages (%). Also, mean of variables before and after the procedure were compared using the paired Mann-Whitney U test.

The efficacy primary endpoint was the percentage of clinical success depending on the indication: target vessel occlusion (arterial hemorrhage), stability or reduction of the aneurysm maximal diameters on CT at 6 months compared to baseline (type II endoleak), growth of future liver remnant by >15% on presurgical CT compared with baseline (portal vein embolization), absence of reflux on ultrasound Doppler at 1 month (varicocele embolization), and >10% reduction of at least 1 diameter on MR or CT at 3 months compared with baseline (angiomyolipoma).

The primary safety endpoint was the expected and unexpected per-procedure serious adverse events related to the EASYX as adjudicated by an independent Critical Events Committee. A total of 3 major device related complications occurred in 2 patients:

• Non-target embolization in a patient with acute hemorrhage related to pseudoaneurysm in which distal coil protection was contraindicated due to a history of Ehlers-Danlos syndrome. 
• Non-target embolization and acute kidney failure in a patient referred for AML embolization which led to complete occlusion of the renal artery.

As for secondary endpoints, 6 patients died before the last study visit (6 months), all deaths adjudicated as the normal evolution of the index illness. The mean pain score was 0.5 ± 1.41 (range, 0–4) for type II endoleaks, 1.6 ± 2.59 (range, 0–8) for active bleeding, and 5.03 ± 2.11 (range, 2–8) for varicocele, assessed using a 0 to 10 visual analog scale in patients under local anesthesia. The satisfaction of the interventional radiologists was >90% for EASYX ease of use, ease of injection, cohesivity, and overall angiographic results.

There was reported operator dissatisfaction with fluoroscopic visibility compared to other ethylene vinyl alcohol-based agents; however, there was significantly less streak artifact on subsequent CT scans. Also, a higher rate of varicocele recurrence was reported, although no associated inflammatory responses were reported, as compared to sclerosants and coils. Overall, the above results demonstrate high user satisfaction and relatively low complications.

Commentary

The authors of this study describe EASYX as both safe and effective for embolization in human subjects for a variety of indications via positive primary and secondary endpoints. The heterogeneous nature of the procedures included introduces bias. Additional limitations include the small number of patients in some indications and short-term follow-up. However, the study provides support for a phase two study as EASYX was generally safe with few complications, easy to use, and effective for its indications. Future direct comparison of EASYX to standard embolics is necessary to establish its clinical value. Additionally, longer term follow-up and larger sample size in future studies will be needed.

Post Author
Colin Marshall, D.O.
PGY-3 Diagnostic Radiology Residency
University Hospitals Cleveland Medical Center
@colinradsIR

Edited and formatted by @NingchengLi

Embolization versus Surgery for Stabilized Patients with Solid Organ Injury

Clinical question
Compare the in-hospital survival after embolization versus laparotomy in hemodynamically unstable patients who responded to resuscitation and initial CT identified isolated solid organ injury.

Take away point
No significant difference was seen between in-hospital survival in those receiving embolization versus laparotomy.

Reference
Embolization versus Surgery for Stabilized Patients with Solid Organ Injury. Aoki, M.. et al. Journal of Vascular and Interventional Radiology, Volume 32, 1150-1155.

Click here for abstract

Study design
Retrospective cohort study from the Japan Trauma Data Bank between 2004-2018.

Funding Source
No funding

Setting
Multi-center.

Figure

Summary

Hemorrhage in the setting of trauma is often successfully managed surgically or with embolization depending on the clinical scenario and resources available. Currently, embolization is recommended for hemodynamically stable patients with solid organ injury, while surgical management is recommended for patients with hemodynamic instability. Those who respond to initial resuscitation may be appropriate for embolization. This study compares in-hospital survival following embolization versus laparotomy in hemodynamically unstable patients with solid organ injury who respond to initial resuscitation.

This is a retrospective cohort study performed in Japan between 2004-2018 using the Japan Trauma Data Bank. Patient selection included: patients over the age of 15, completion of abdominal CT, liver and/or splenic injury, sBP <90mm Hg and received a blood transfusion within 24 hours. Patient exclusion included: severe abdominal injury (AIS >3), except for splenic or liver injuries, AIS of 6, dead on arrival, administration of CPR and aortic cross-clamping. Patients were then divided into groups based on having received laparotomy or embolization (see figure above). The primary outcome was in-hospital survival. Secondary outcomes included, complications, length of hospital stay, percentage of patients discharged to home, and rate of splenectomy. Notable analysis technique included propensity score matching analyses, comparing the following models: original cohort (PSM1), cohort minus the penetrating mechanism (PSM2), and cohort adjusted by the time to transfusion and to treatment (PSM3).

Of the baseline characteristics, there were significant differences in sex, sBP, GCS and ISS in PSM 1 and 2, and GCS in PSM3. There was no significant difference between laparotomy and embolization in the 3 propensity score matching models regarding in-hospital mortality, liver injury, splenic injury, time to treatment or analyzed complications. Notable limitations include lack of information on which organ was embolized, their definition of hemodynamic instability and possible confounders not included in their PSM analysis. In addition, the authors note a high degree of access to CT scanners and a short time to embolization. This may be due to CT scan and embolization availability in many of the OR suites in Japan included in this study.

Commentary

Regardless of OIS scores, this study demonstrates no significant difference in in-hospital mortality between laparotomy and embolization in stabilized patients who had received a CT scan. This data helps underscore the utility of endovascular techniques in trauma, particularly those that may be deemed hemodynamically unstable. The authors define instability as a sBP <90 mm Hg and having received a blood transfusion. The American College of Surgeons defines hemodynamic instability “as global or regional perfusion that is not adequate to support normal organ function”. They also note that relying on sBP is not sufficient, due to multiple compensatory mechanisms that exist to prevent hypotension. Overall, hemodynamic instability is often a gestalt, which is challenging to define by objective numbers. Additionally, although there is high availability of CT scans in Japan, the inclusion criteria of having received a CT scan often suggests some element of stability.

The greatest challenge is the applicability of these findings in healthcare settings where access to CT may be limited or prompt endovascular treatment may be logistically challenging. In this study, patients had timely access to both imaging and endovascular treatment. Time to treatment is immensely important in trauma patients, therefore care should not be delayed to pursue an endovascular option. If the patients by definition are hemodynamically unstable, the facility should have access to hybrid operating rooms or the ability to rapidly transfer to surgical management. In the US, the majority of hospitals are not level 1 trauma centers, and are often able to surgically manage patients more quickly. In the correct clinical and healthcare setting, these findings demonstrate endovascular treatments are an appropriate treatment option in the unstable trauma patient. Future research noting specific organ embolization and treatment techniques may help establish protocols and help guide clinical decision making.

Post Author
Marissa Stumbras, MD
Interventional Radiology Resident, PGY3
Oregon Health & Science University
@MarissaStumbras

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Catheter-Directed Hemorrhoidal Dearterialization Technique for the Management of Hemorrhoids: A Meta-Analysis of the Clinical Evidence

Clinical question
Is catheter-directed hemorrhoidal dearterialization (CDHD) a safe and effective treatment strategy for the management of hemorrhoidal bleeding?

Take away point
Preliminary evidence supports CDHD as an effective, safe treatment for grade I-III hemorrhoids and suggests embolization with a combination of coils and particles decreases rebleeding rates compared to coils alone.

Reference
Makris G,Thulasidasan N, Malietzis G, Kontovounisios C, Saibudeen A, Uberoi R, Diamantopoulos A, Sapoval M, Vidal V. Catheter-Directed Hemorrhoidal Dearterialization Technique for the Management of Hemorrhoids: A Meta-Analysis of the Clinical Evidence. J Vasc Interv Radiol. 2021;32(8):1119-1127. doi:10.1016/j.jvir.2020.03.548

Click here for abstract

Study design
Systematic review and meta-analysis.

Funding Source
No reported funding.

Setting
Studies selected from PubMed, Cochrane, and Scopus databases.

Figure

French bleeding score before and after rectal artery embolization.

Summary

Catheter-directed hemorrhoidal dearterialization (CDHD) for the treatment of hemorrhoidal bleeding is an emerging technique described in small studies and case reports as a minimally invasive alternative to surgical management. In an effort to evaluate the current evidence regarding the efficacy and safety of CDHD for rectal bleeding, the authors performed a systematic review and meta-analysis of 14 studies assessing CDHD.

Keyword searches via PubMed, Cochrane, and Scopus were performed to include clinical studies that evaluated patients with confirmed rectal bleeding secondary to hemorrhoids, treated patients with CDHD and reported clinical outcomes, and recruited five or more patients. Animal studies and case reports were excluded.

Data were extracted regarding study design, patient characteristics, disease burden, technique details, clinical follow up (including complications and symptom recurrence), and technical and clinical success rates. Statistical analyses were performed, primarily calculating and comparing means (range; standard deviation) via t tests.

A total of 14 studies met criteria (8 prospective, 6 retrospective) with a total of 362 patients. In all studies, the superior rectal artery (SRA) was embolized, most commonly using a combination of coils and other embolics (including particles, spheres, polyvinyl alcohol, gelatin sponge, and/or ethanol) versus coils alone.

There was no statistical difference among technical success rates, with an average of 97.8% (90-100%; 3.5%). Mean clinical success was 78.9% (66-96.9%; 10.6%). Four studies (n=98) reported bleeding score with a mean pre-embolization score of 6.78 (5.5-7.6; 0.90) and post-embolization score of 3.95 (2.8-5.0; 0.90) (p=.004). Average bleeding recurrence over the mean maximum follow-up of 12.1 months (1-28; 7.3), was 22.5% (5.4-44%). Of these, five studies (n=111) used coils alone for primarily grade II hemorrhoids with a mean rebleeding rate of 21.5% (0-44%; 18.2), one study used particles alone for primarily grade III hemorrhoids with a mean rebleeding rate of 29%, and four studies (n=108) used a combination of coils and particles for primarily grade III hemorrhoids with a mean rebleeding rate of 10.1% (5-15.7%; 4.8). Rebleed rates were statistically lower in the coils plus particles group compared to the coils alone group (p<.0001).

Reported major complications included one instance of IMA dissection that did not result in bowel ischemia, and one instance of puncture site arterial thrombosis and patient death.

Commentary

The authors perform a systematic review of 14 studies describing CDHD for the treatment of hemorrhoidal bleeding in a total of 362 patients. The aggregation of data in this meta-analysis offers more robust results compared to individual smaller studies, which more confidently supports the conclusion that CDHD is safe and effective in treating hemorrhoidal bleeding.

The authors discuss that there is a significant lack of comparative data between CDHD and surgery. Only one nonrandomized, non-blinded study attempted to directly compare stapled hemorrhoidectomy with coil and particle SRA embolization and reported significantly better pain and bleeding scores in the CDHD group (which included older patients with more comorbidities). They also discuss the lack of standardized technique, although highlight the statistically lower rebleed rates in studies that used a combination of coils and particles.

The mean follow-up period of 12.1 months likely underestimates the true complication and rebleeding rates. Additionally, publication bias against inconclusive or negative results and the absence of randomized, controlled trials introduce substantial confounds that may be amplified in subgroup analyses. Nonetheless, this meta-analysis is a valuable summarization of the existing primary data suggesting CDHD as a safe and effective treatment strategy for hemorrhoidal bleeding. Future studies should focus on direct comparison with surgical treatment to more confidently inform clinical decision-making.

Post Author
Catherine (Rin) Panick, MD
Resident Physician, Integrated Interventional Radiology
Dotter Interventional Institute
Oregon Health & Science University
@MdPanick

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Genicular Artery Embolization for Refractory Hemarthrosis following Total Knee Arthroplasty: Technique, Safety, Efficacy, and Patient-Reported Outcomes

Clinical question
Is genicular artery embolization safe and effective for treatment of refractory hemarthrosis following total knee arthroplasty?

Take away point
Targeted genicular artery embolization with spherical embolics is an effective treatment for recurrent hemarthrosis with infrequent major complications. Repeat embolization should be considered in cases of recurrence following initial therapy.

Reference
Cornman-Homonoff, J., Kishore, S.A., Waddell, B.S., Kesler, J., Mandl, L.A., Westrich, G.H., Potter, H.G., Trost, D.W., 2021. Genicular Artery Embolization for Refractory Hemarthrosis following Total Knee Arthroplasty: Technique, Safety, Efficacy, and Patient-Reported Outcomes. Journal of Vascular and Interventional Radiology 32, 1128–1135.. doi:10.1016/j.jvir.2021.04.020

Click here for abstract

Study design
Retrospective review of patients who underwent genicular artery embolization between 2010 – 2020 at a single institution. Inclusion of patients who had previous total knee arthroplasty and experienced recurrent refractory hemarthrosis diagnosed either by clinical exam or arthrocentesis.

Funding Source
No reported funding

Setting
Academic setting:
Department of Radiology, Division of Interventional Radiology, NewYork-Presbyterian/Weill Cornell Medical Center.
Department of Radiology, Division of Interventional Radiology Memorial Sloan Kettering Cancer Center.
Department of Orthopedic Surgery, Department of Medicine and Department of Radiology and Imaging Hospital for Special Surgery.
New York, New York

Figure

Summary

Recurrent and repetitive bleeding into the joint (hemarthrosis) can be a debilitating complication of total knee arthroplasty. Current literature estimates about 0.1 – 1.6% incidence following surgery. Short term sequelae of recurrent hemarthrosis include wound breakdown, poor healing, and joint sepsis. Long term sequelae include painful swelling, joint stiffness, and impaired function. Impingement secondary to hypertrophic synovium is the most common cause. Current regimens include initial conservative measures such as immobilization and arthrocentesis. A large subset of patients will however require intervention for refectory hemarthroses with current therapies including arthroscopic and open synovectomy. The purpose of this study was to examine the technical aspects, safety, and efficacy of genicular artery embolization for postoperative hemarthrosis after total knee arthroplasty.

Pertinent demographic data was collected on patients meeting the inclusion criteria for the retrospective review as described above. All patients were initially managed conservatively and had pre-procedure MR angiography demonstrating synovial hyperemia as the causative factor. Pertinent exclusion criteria included additional causes such as presence of pseudoaneurysm formation or AV malformation. 81 patients were included with 1 patient having bilateral knee treatment during the study time frame. Patients had a mean age of 65 years, body mass index of 28 kg/m^2 with 57% male. 2.6% of patients had bleeding diathesis, 23.1% of patients were on antiplatelet therapy only, 5.1% of patients were on anticoagulation only, and 6.4% were on both. Average time from surgery to symptom onset was 14.9 months, average time from symptom onset to first embolization was 9.2 months.

Technical success was defined as angiographic resolution of synovial blush following treatment and clinical success was defined as resolution of hemarthrosis on follow up. Clinical follow up was obtained 7-14 days following embolization with additional follow up obtained in 3-month intervals via telephone interviews. All patients achieved technical success. Clinical success was identified as 56.1%, 79.3% and 85.4% following 1st, 2nd and third treatments. Complications were classified using SIR adverse event criteria, with mild, moderate, and severe complications. 12.8% (17) of treatments resulted in complications with the majority (15) considered mild. 14 of these were episodes of periarticular skin mottling, appropriately treated and responsive to conservative measures. There was a single moderate complication, an access site pseudoaneurysm, treated percutaneously with thrombin injection. The single severe complication was septic arthritis requiring surgery and prosthesis removal.

Commentary

This study adds to the existing literature describing genicular artery embolization (GAE) for refractory hemarthrosis with a larger data set and patient cohort. The authors evaluated the efficacy of GAE with results comparable to the existing data, achieving clinical success of 85%, with reported rates of 80-92% in the existing series. An important aspect of the study was the focus on repeat embolization. Repeat intervention was pursued in 34% of patients with refractory hemarthrosis with increasing clinical success with each additional treatment. 7 knees in the study underwent 3 interventions. As the authors mentioned, this may lead some to believe that initial treatments may have been incomplete despite immediate technical success. However, the need for repeat embolization may also be attributed to collateralization of the hyperemic synovium with subsequent incomplete regression and continued synovial impingement causing refractory hemarthrosis. Future studies and efforts may be well suited to delineate the timing of repeat intervention in relation to initial and subsequent symptomatology.

As mentioned above, the complication rate for the series was quite low. The most common complication identified was periarticular skin mottling. All instances identified in this series were effectively managed with conservative measures alone. Additionally, the authors noted the skin mottling was less prevalent when using larger particles (greater than 300 micron). The most severe complication was septic arthritis following embolization which required prosthesis removal and replacement. Of note, the affected patient did receive arthrocentesis following embolization and prior to the joint infection, making the exact etiology unclear. Prior studies have also described singular instances of septic arthritis with all protocols requiring preprocedural antibiotics.

The limitations of this study remain its retrospective analysis and somewhat subjective quality. Throughout the 10-year course of the study, the authors acknowledge some fine tuning of the technical aspects of the procedure; including particle size selection which introduced some data heterogeneity. Additionally, most cases were performed by a single operator which may reduce its overall reproducibility and generalizability. Follow up was obtained via telephone interviews which may introduce bias from patient reviews. The patients were referred at the discretion of the treating orthopedic surgeon after variable conservative management and symptomatology. A standardized referral pattern and treatment would be beneficial for future studies.

Post Author
Ahmad Hashmi, MD
PGY-5 ESIR,
University Hospitals Cleveland Medical Center,
Case Western Reserve University
@afhashmi2

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Perioperative Blood Loss after Preoperative Prostatic Artery Embolization in Patients Undergoing Simple Prostatectomy: A Propensity Score‒Matched Study

Clinical question
Is preoperative prostatic artery embolization (PAE) safe and effective at reducing intraoperative blood loss?

Take-away point
Preoperative bilateral PAE safely and effectively reduces intraoperative bleeding and operative time.

Reference
Sare A, Kothari P, Cieslak JA, et al. Perioperative blood loss after preoperative prostatic artery embolization in patients undergoing simple prostatectomy: a propensity score‒matched study. Journal of Vascular and Interventional Radiology. 2021;32(8):1113-1118.

Click here for abstract

Study design
Retrospective cohort study

Funding source
Self-funded or unfunded

Setting
Single institution, Rutgers – New Jersey Medical School, Newark, NJ

Figure




Figure. (a) Mean estimated blood loss (mL) with standard deviations during prostatectomy in the group with embolization before surgery versus control group. (b) Mean operative time (minutes) of prostatectomy in the group with embolization before surgery versus control group. PAE = prostate artery embolization.

Summary

Benign prostatic hyperplasia (BPH) is a common cause of lower urinary tract symptoms, affecting most men over the age of 60 years of age and >80% of men at or above the age of 70. First-line treatment has historically involved lifestyle modifications and pharmacotherapy with 5-a-reductase inhibitors, a-blockers, and phosphodiesterase inhibitors, with surgery being recommended if these measures fail to provide adequate relief. Surgical options include TURP and prostatectomy, with complication rates increasing with increased prostate size. The most common complication is bleeding requiring transfusion, which has been shown to occur in 11.9% of patients undergoing open prostate resection, which is generally performed for patients with larger prostates. Preoperative embolization has been shown to be a safe and effective method of reducing operative estimated blood loss (EBL), transfusions, and hospital length of stay (LOS) for resection of a variety of hypervascular tumors, but has not yet been evaluated in patients undergoing prostatectomy.

In this retrospective case series, 63 patients with prostatic hypertrophy with severe lower urinary tract symptoms (LUTS) were analyzed. All patients had prostates with mass > 80 grams and subsequently underwent prostatectomy. Patients either underwent bilateral PAE or no embolization prior to the procedure; patients undergoing unilateral PAE were excluded. Data collected included demographics, comorbidities, preoperative prostate volume (by transrectal ultrasound), method of prostatectomy, PAE technical details, pre- and post-operative hematologic labs, EBL, operative time, transfusion, and duration of post-operative continuous bladder irrigation (CBI). In patients who underwent embolization, bilateral PAE was performed using 250-μm hydrogel microspheres until cessation of anterograde flow, followed by gelfoam slurry injection. Patients then underwent either robotic prostatectomy or open suprapubic prostatectomy within 2 weeks of PAE.

60 patients were analyzed in this study, including 16 patients undergoing bilateral PAE and 44 patients in the non-embolization arm. 32 of the non-embolization patients were used from the 44 for 2:1 propensity score-matching. In the embolization group, 11 patients underwent robotic prostatectomy while 5 underwent open suprapubic prostatectomy compared to 10 and 22 patients respectively in the non-embolization group. Demographics and baseline characteristics between groups were not significantly different. Median time between PAE and prostatectomy was 6 days (4-18 days). Mean EBL was 303 ± 219.7 ml in the PAE arm compared to 545 ± 380 ml in the non-embolization arm (p < 0.01). Mean operative time was 140.5 ± 35.4 minutes in the PAE arm versus 180.5 ± 56.6 minutes in the non-embolization arm (p < 0.01). Change in hemoglobin during surgery was 2.16 g/dl in the PAE group and 3.50 g/dl in the non-embolization group (p = 0.020). 6% of patients in the PAE group underwent transfusion compared to 19% in the non-embolization group, but with a mean of 0.19 units per patient in the PAE group versus 0.44 in the non-embolization group, which was not significantly different (p = 0.334). LOS did not significantly differ between groups, and no major or minor complications occurred.

Commentary

The AUA recommends surgery as standard of care for BPH; however, large prostates can be challenging to treat and have higher rates of bleeding complications. Prostate artery embolization has been shown to be safe and effective for treating both prostate related hematuria and LUTS. This study demonstrated a decrease in operative blood loss and mean operative time in patients undergoing preoperative PAE before prostatectomy for prostates of large size (>80 g). It did not, however, demonstrate a statistically-significant reduction in LOS or transfusion. The lack of difference in transfusions may be due to low sample size in combination with variability in transfusion thresholds between Urologists. The only prior study similar to the one summarized here found decreased LOS and intraoperative blood loss, but only used change in hematologic lab studies and did not assess EBL. This does suggest that lack of significant difference in LOS in this study may be due to its small sample size. This is an acknowledged limitation of the study in addition to its retrospective nature. One challenge in standardization posited by the authors is the relatively large range of time between PAE and prostatectomy, which may have resulted in differences in the development of collateral circulation prior to surgery, resulting in clinically-significant differences in blood loss. Future investigations should focus on randomized trials involving multiple high-volume centers as well as research into the timeline of collateral generation in the prostatic vasculature. Finally, it would be interesting to evaluate the effectiveness of unilateral dominant PAE for the purpose of operative blood loss reduction.

Post Author
Jared Edwards, MD
General Medical Officer
Medical Readiness Division
Naval Surface Forces Pacific, San Diego, CA
@JaredRayEdwards

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Percutaneous Image-Guided Core Needle Biopsy of Neuroendocrine Tumors: How Common Is Intraprocedural Carcinoid Crisis?

Clinical question
What is the incidence of carcinoid crisis, physiologic disturbances, and other complications during percutaneous image-guided core needle biopsy of neuroendocrine tumors (NETs) in the lung and the liver?

Take away point
Percutaneous image-guided core biopsy of NETs is quite safe, with very low complication rate and no definite carcinoid crisis within the current small cohort.

Reference
Percutaneous Image-Guided Core Needle Biopsy of Neuroendocrine Tumors: How Common Is Intraprocedural Carcinoid Crisis? Jang, Samuel et al. Journal of Vascular and Interventional Radiology, Volume 32, Issue 5, 2021, Pages 745-751.

Click here for abstract

Study design
Single-center retrospective (10 years) cohort study, including 106 biopsies from 16 patients with pathology proven diagnosis of carcinoid or NET.

Funding Source
Self-funded or unfunded.

Setting
Mayo Clinic Department of Radiology, Rochester, Minnesota

Figure

Figures: (Left) Percutaneous CT-guided biopsy of a 2.3-cm lesion in the right upper lobe. Histopathologic diagnosis was ‟typical carcinoid tumor.” (Right) Percutaneous US-guided biopsy of a 3.0-cm lesion with a hypoechoic rim in the peripheral posterior right hepatic lobe. Histopathologic diagnosis was ‟well-differentiated neuroendocrine tumor.”

Summary

Neuroendocrine tumors (NETs) can produce vasoactive hormones that cause a range of physiologic events which are collectively known as carcinoid syndrome. It predominantly occurs in serotonin-producing tumors of the small intestine and patients with hepatic metastasis. A potential life-threatening complication of carcinoid syndrome is carcinoid crisis, caused by the sudden massive release of vasoactive substances that precipitate physiologic crisis, triggered by interventions and manipulation of these tumors. Incidence of carcinoid crisis has been studied in multiple therapeutic procedures, however, no retrospective cohort studies that examine the rate of adverse physiologic effects from image-guided percutaneous biopsy of NETs have been completed.

Retrospectively 106 computed tomography (CT) or ultrasound (US)-guided core needle biopsies of lung and liver NETs from 95 patients were reviewed over a 10 year period (Jan 2010 to Jan 2020). Patients’ mean age was 64 ± 13 years, and 48% were female. Small bowel primary site was the most common (33%). Most patients had widely metastatic disease, while only 32 patients (34%) had fewer than 5 lesions at the time of biopsy. Thirty two (34%) patients had pre-existing symptoms of carcinoid syndrome, the most common symptom being diarrhea (88%). The mean tumor size was 3.2 ± 2.6 cm, and mean number of passes was 3.4 ± 1.6. A 17/18-gauge needle was used in 91% of the biopsies. Thirteen (12%) patients received either outpatient or prophylactic octreotide. Patients’ malignancies were deemed functional or nonfunctional based on clinical documentation determined by the patients’ oncologist 30 day prior to biopsy, of which 36% of the tumors were deemed functional. Neuroendocrine markers including were available for Potential physiological disturbances related to the biopsies were analyzed based on nursing documentation noting the exact times of the biopsies, and individual patients’ oxygen saturation, heart rate, blood pressure, and respiratory rate immediately prior to the first tumor passage and just after the last passage.

Carcinoid crisis as it was defined in the study was not encountered in the studied cohort. One major complication and four minor complications were encountered. Paired t test was used to compare pre and post biopsy physiological data, of which no statistically significant change was observed, even in multiple subgroup analysis of patients with proposed risk factors. Mean and standard deviation were used for continuous variables, and frequency counts with percentages were used for categorical variables. No previous studies of NET biopsy described carcinoid crisis as a complication. Taken in context with the current study, the authors conclude carcinoid crisis from core biopsy is extremely rare (only 4 case reports), and percutaneous image-guided biopsy of NETs can likely be performed without prophylactic octreotide administration.

Commentary

The authors acknowledge study limitations, including limitations of their statistical analysis due to the low number of complications, no standard panel of pre-procedure neuroendocrine markers for each patient, and the subjective nature of documenting pre-existing carcinoid crisis based on EMR documentation. However, I believe this study was well-performed and legitimate for a single center retrospective cohort, especially considering the rarity of NET and a10-year time frame. The study is unique in that it is the only study to analyze intraprocedural physiologic data in the context of biopsy of NETs, showing no statistically significant change from pre- to post-biopsy, even in subgroup analysis.

I agree with the authors' clinically significant conclusions, and think they have future implications in guiding proceduralists' approach to biopsy of NETs. The authors make a strong case that carcinoid crisis in percutaneous biopsy of NET is extremely rare, in presenting both the current study and other similar biopsy studies of NET. They also conclude prophylactic octreotide administration prior to percutaneous biopsy is likely not necessary regardless of tumor burden, tumor functional status, and neuroendocrine markers. The authors contextualize this conclusion in saying that the proceduralist should remain vigilant of carcinoid crisis and prepared to respond swiftly.

Post Author
Gregory Rufener, MD
Radiology Resident (PGY-4)
Department of Diagnostic Radiology
Oregon Health and Science University, Portland, Oregon
Twitter: @gregoryrufener

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Effectiveness of Thermal Ablation and Stereotactic Radiotherapy Based on Stage I Lung Cancer Histology

Clinical question
Is there a difference in effectiveness of thermal ablation (TA) and stereotactic body radiotherapy (SBRT) as initial treatments for stage I lung cancer depending on histologic subtypes?

Take away point
Overall survival following TA and SBRT for stage I lung cancer is comparable for most histologic subtypes, except for non-small cell neuroendocrine tumors (NETs), where overall survival is higher after TA.

Reference
Uhlig J, Mehta S, Dendy Case M, Dhanasopon A, Blasberg J Homer R, Solomon S, Kim H. Effectiveness of Thermal Ablation and Stereotactic Body Radiotherapy Based on Stage I Lung Cancer Histology. J Vasc Interv Radiol. 2021; 32:1022-1028. doi.org/10.1016/j.jvir.2021.02.025

Click here for abstract

Study design
Retrospective, database analysis using 2004-2016 data from the National Cancer Database.

Funding Source
No reported funding.

Setting
National database study via the National Cancer Database; USA.

Figure



The effectiveness of thermal ablation (TA) and stereotactic body radiotherapy (SBRT) according to histologic lung cancer subtypes.

Summary

Histologic subtypes of lung cancer are known to affect initial treatment and prognosis. In patients who are not surgical candidates or who have an unfavorable comorbidity profile for chemotherapy, thermal ablation (TA) or stereotactic body radiotherapy (SBRT) are options, but comparative effectiveness data is lacking. The authors perform a retrospective database analysis comparing effectiveness of TA and SBRT based on histologic subtype for initial treatment of stage I lung cancer.

The National Cancer Database was queried for patients having undergone initial treatment for stage 1 lung cancer with TA or SBRT from 2004-2016. Patients were excluded if they were <18 years of age, received surgery or chemotherapy, had unknown survival or follow up, or had a lung cancer histologic subtype that did not fall under the 2015 World Health Organization (WHO) classification system. The Charleston Comorbidity Index (CMI) was used to stratify comorbidities.

Primary outcome was overall survival defined as time from treatment until patient death or censoring. Initial data were evaluated and nearest-neighbor propensity score matching was completed with a 1:5 ratio of patients receiving TA versus SBRT. Propensity score matching was verified with a Kolmogorov-Smirnov test.

A total of 28,425 patients met criteria with 947 having undergone TA and 27, 478 having undergone SBRT. Propensity score matching was completed using the aforementioned variables identified in the multivariable logistic regression. Matched cohorts included 817 patients receiving TA and 4,085 patients receiving SBRT. Subgroup analyses were stratified according to histologic subtype as defined by the WHO 2015 classification system and included adenocarcinoma, non-NET large cell carcinoma, small cell carcinoma, non-small cell NET, and squamous cell carcinoma. Overall survival curves were generated via Cox regression and hazards ratios were calculated.

From initial analyses using the full nonmatched cohorts, TA was independently associated with Caucasian race, a greater number of comorbidities, earlier year of cancer diagnosis, smaller tumor diameter, tumor location in the lower lobe, facility location in the Middle Atlantic or New England regions, and tumor subtype of non-small cell NETs.

There was no significant difference in overall survival between TA and SBRT overall (HR=1.07, p=.13). In the subgroup analysis, OS was significantly longer for TA versus SBRT in patients with non-small cell NETs (HR=0.48, p=.04). There was no statistically significant difference in OS in the other histologic type subgroups [adenocarcinoma (HR=1.08, p=.20), non-NET large cell carcinoma (HR=2.12, p=.25), small cell carcinoma (HR=.93, p=.82), and squamous cell carcinoma (HR=1.12, p=.12)].

The authors discuss why TA may be more effective in non-small cell NETs. NETs are often well-defined, smaller diameter, and thus a better target for TA than other subtypes. Additionally, NETs are known to be less aggressive than other subtypes and are comparatively radioresistant.

While SBRT is considered the standard of care in patients with NSCLC and less invasive than TA, it often incurs longer lasting complications such as fatigue, pneumonitis, and chest wall pain. In comparison, TA has known risks of pneumothorax and pleural effusion, but can be completed on a single session, which is more convenient for the patient and more cost effective.

Commentary

The authors evaluate the effectiveness of TA versus SBRT as initial treatment for patients with stage I lung cancer among histologic subtypes using data from the National Cancer Database. Several limitations exist, most inherent to the database design. Data on combination or repeat/salvage treatment, details of procedural complications, and cancer-specific recurrence were not available. This precluded evaluation of complication rate, as well as limits the overall specificity of the conclusions. Additionally, lack of technical details (such as probe count and type of ablation) limit further comparison between TA and SBRT. Lastly, there are intrinsic limitations to a retrospective study design with propensity score matching; a prospective, randomized trial would certainly be a more robust evaluation.

The main advantage of this study is the large-scale nature allowing for ample power and improved reliability of the primary endpoint that showed increased OS in patients with non-small cell NETs receiving TA versus SBRT. Interestingly, the non-small cell NET subtype was independently associated with TA, suggesting that providers may already more strongly favor TA as initial treatment in this subgroup.

The authors also offer commentary on their results regarding the demographic factors associated with TA. Despite broad results showing comparable effectiveness of TA and SBRT, TA is disproportionally utilized in the northeastern US and in Caucasian patients. The authors hypothesize this may be related to differences in socioeconomic status, insurance status, or comorbidity profile, highlighting known healthcare disparities in the US. A lack of provider awareness of TA may also contribute to this distribution.

While intrinsically limited, this large-scale study still offers a valuable insight into the effectiveness of TA and SBRT in treating the histologic subtypes of stage I lung cancer and suggests considering TA over SBRT as initial treatment in nonsurgical patients with stage I non-small cell NETs. This study also raises awareness of TA as an effective alternative treatment for stage I lung cancer in the appropriate clinical setting.

Post Author
Catherine (Rin) Panick, MD
Resident Physician, Integrated Interventional Radiology
Dotter Interventional Institute
Oregon Health & Science University
@MdPanick

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