The efficacy of palliative radiation therapy in the treatment of recurrent and metastatic ovarian cancer.

Abstract

129 Background: Ovarian cancer is the 2nd most common gynecologic malignancy with surgery and platinum-based chemotherapy as the mainstay of initial treatment. However, ovarian cancer has generally high rates of recurrence and metastasis after primary therapy. For patients with progressive or symptomatic disease, radiation therapy (RT) can be utilized as an effective option for palliation. Methods: A retrospective review was conducted of patients treated with palliative RT for symptomatic or recurrent ovarian cancer between 2015-2019 at a single institution. 17 women were identified who received 20 courses of RT. Response was classified as complete response (CR), partial response (PR), and progressive disease (PD). Overall response rate (ORR) was the sum of CR and PR. Results: Median age at RT was 57 (range 36-76). Histologic subtypes were high grade serous (65%), low grade serous (12%), clear cell (12%), and other (12%). The most common indications were pain (65%), bleeding (30%), and asymptomatic progression (20%). 18 of 20 RT courses were delivered to soft tissue or nodal metastases. RT techniques included 2D/3D (60%), IMRT (30%), and SBRT (10%). Dose ranged from 20-60 Gy in 3-28 fractions. 20 Gy in 5 fractions (25%) and 30-31 Gy in 10 fractions (25%) were most common. Of the 16 RT courses for symptomatic disease, clinical ORR was 87.5% within 3 months of RT (50% PR and 37.5% CR). 3 treatments had sustained response beyond 3 months. 2 developed PD. Of 11 RT courses with follow-up imaging, radiographic ORR was 36.1% (27% PR and 9.1% CR) within 3 months of RT. 1 had sustained PR beyond 3 months. Of the 10 RT courses for symptomatic high grade serous histology, PR and CR was seen in 50% and 40% of patients within 3 months (90% ORR). Conclusions: Palliative RT offers high rates of clinical response for symptomatic patients with metastatic ovarian cancer within 3 months of treatment delivery. Rapid clinical response rates were particularly favorable for those with high grade serous histology. RT should be considered as a standard palliative option for patients with symptomatic ovarian cancer metastases. Further prospective studies are warranted to establish the optimal timing, dose, and relation to chemosensitivity in this setting.