Image-Guided Percutaneous Thermal Ablation of Oligometastatic Ovarian and Non-Ovarian Gynecologic Tumors

Clinical question
What is the role of percutaneous thermal ablation (TA) for secondary cytoreduction in patients with metastatic gynecologic tumors?

Take away point
TA is a reasonable option for secondary cytoreduction in patients with metastatic gynecologic tumors, with an overall survival rate of 37.5 months and a local progression-free survival rate of 16.5 months.

Reference
Image-Guided Percutaneous Thermal Ablation of Oligometastatic Ovarian and Non-Ovarian Gynecologic Tumors. Yuan, F.. et al. Journal of Vascular and Interventional Radiology, Volume 32, 729-738.

Click here for abstract

Study design
Retrospective, single-center, cohort study.

Funding Source
No funding

Setting
Single-center.

Figure

Summary

Metastatic gynecologic tumors unfortunately have a particularly low patient survival rate. Gynecologic tumors include ovarian, uterine/endometrial, cervical, and vaginal neoplasms. The current treatment recommendations to maximize cytoreduction generally include primary surgical resection, chemotherapy and radiotherapy. Overall, the residual tumor volume after primary surgical resection is the main prognostic factor in long-term survival. As with many image guided and minimally invasive procedures, TA results in shorter hospital stays, lower procedure related risks and is often better tolerated by patients who are not surgical candidates. The existing literature thus far has focused primarily on ovarian tumors that have metastasized to the liver. In addition, the role of secondary cytoreduction, such as TA, in gynecologic tumors, is not as well studied.

A retrospective, single-center, cohort study of 42 patients with metastatic gynecologic cancer was performed over two decades. All patients received primary surgical resection and chemotherapy. Over half received adjunctive radiotherapy. The most common treated tumor locations with TA were liver/liver capsule (74%), lungs (13%), and peritoneum (9%). The TA modalities used included radiofrequency, microwave ablation and cryogenic ablation. Following the procedure, patients either underwent contrast-enhanced-CT immediately after the treatment. If there was residual intratumoral enhancement and/or an incomplete zone of ablation, they were immediately re-treated. After successful treatment(s) the patients completed a contrast-enhanced-MR prior to discharge. Contrast enhanced-CT or MR was repeated one month post-treatment to evaluate treatment response. Adequate response to treatment was deemed as no intra or peri-tumoral enhancement. Patients were subsequently followed with repeat imaging every three months. Patients that were lost to follow-up or had indeterminate treatment responses were not included in their efficacy or survival analyses. Adverse reactions were based on the Society of Interventional Radiology reporting standards.

Local tumor control: Following the first TA treatments, the technical success rate was 95.6%; 109 targeted tumors had a complete tumor response. Two treated tumors had residual tumor on follow-up imaging and required a second ablation session. This lead to an overall primary treatment efficacy of 94.2%, with a mean follow-up period of 10 months. During this follow-up period, 8.5% (n=8/94) of the ablated tumors developed recurrence requiring additional treatments, of which 4/5 responded, resulting in a secondary efficacy of 80%.

Patient survival: The median survival following the initial ablation for all tumor types was 37.5 months (SE +/-; 95% CI, 27.7-47.3). Despite lacking statistical significance, the overall survival rate of metastatic ovarian tumors was 37.5 months (SE +/- 7.4; 95% CI, 23-52) and metastatic non-ovarian gynecologic tumors was 52.1 months (SE +/- 19.7; 95% CI 13.5-90.8). Time to progression in those with tumor recurrence was a median of 4.1 months (SD +/- 4.5 months).

Adverse events: The major adverse event rate was 4.8% (n=2/42). The major adverse events included: hepatic abscess (n=1), pleural effusion (n=1), chest pain (1), and small pneumothorax (1). All patients recovered well following appropriate standard treatment.

Commentary

This study explores the use of TA as secondary cytoreduction in patients with metastatic gynecologic tumors. A major limitation is that this is a retrospective and single-center study that spanned 20 years. Advances in chemotherapy, medical devices and standard of care likely have changed over that time-frame and may have affected outcomes.

Despite this study being one of the largest of TA and metastatic gynecologic tumors, there were still only 42 patients included. Subsequently, the non-ovarian subtypes of gynecologic tumors were small (e.g. n=5 for endometrial cancers) and therefore lacked comparative power. Although the tumors included in this study are all of gynecologic origin, they often have different prognostic factors, survival rates, chemotherapy and radiation regimens. Additionally, the overall five year survival rate varies greatly among patients with different gynecologic tumors and distant tumor spread. For example: ovarian epithelial=30%, ovarian-stromal=74%, cervical=17% and endometrial/uterine=17%.

Given the major differences in five year survival rates and treatment regimens, the greatest limitation is adequate interpretation of the survival benefits of this procedure. As mentioned previously, residual tumor after primary surgical resection is a major prognostic factor in long term survival. However, the role of secondary cytoreduction with TA is less clear. Based on different tumor-types, prior research has established that not all gynecologic tumors have survival benefits beyond chemotherapy. This leaves a few questions to be answered for future research. How does secondary cytoreduction affect survival rate in each gynecologic tumor sub-type? Do different tumor characteristics play a role in response? How does secondary cytoreduction with surgery versus TA compare in a prospective research setting? A larger, prospective, multi-center study may help clarify these findings and establish when secondary cytoreduction with TA is most appropriate. Despite the minimally invasive nature of TA, these patients often have a poor survival rate, so quality of life and judicial use of additional procedures and subsequent hospitalizations is of particular importance. Overall, this study provides an excellent foundation for further research and highlights TA as a useful tool in treatment of metastatic gynecologic tumors.

Post Author
Marissa Stumbras, MD

Interventional Radiology Resident, PGY2
Oregon Health & Science University
@MarissaStumbras