(P080) Favorable Outcomes Using Radiation Therapy After Chemotherapy in the Management of Primary, Recurrent, and Metastatic Ovarian Cancer

Carolina E. Fasola, MD, MPH, Daniel S. Kapp, MD, Elizabeth Kidd, MD; Department of Radiation Oncology, Stanford University School of Medicine

PURPOSE: This study aimed to evaluate treatment outcomes and toxicity of radiation therapy (RT) in patients with primary, recurrent, or metastatic ovarian cancer following treatment with chemotherapy.

MATERIALS AND METHODS: We reviewed the medical records of 133 patients with stage I–IV ovarian cancer treated at our institution between 1997 and 2014. Patients underwent the following treatment regimens after initial tumor debulking surgery and chemotherapy: whole-abdominopelvic RT (n = 15), RT at the time of localized recurrence (n = 57), or palliative RT in the metastatic setting (n = 61). Freedom from progression (FFP) and overall survival (OS) were estimated using Kaplan-Meier analysis.

RESULTS: The median follow-up time among all patients was 15.6 months (range: 1–200 mo) and 22.5 months among patients treated with curative intent for primary or recurrent disease. For patients treated with curative intent, the majority had International Federation of Gynecology and Obstetrics (FIGO) stage III disease at initial presentation (65%) with papillary serous histology (47%). A total of 55 (76%) patients had platinum-sensitive disease, and 17 (24%) were considered platinum-resistant. The median prescription RT dose in this cohort of patients was 45.9 Gy (range: 30–57.6 Gy) delivered using three-dimensional (3D) conformal RT (n = 60) or intensity-modulated radiotherapy (IMRT)/ stereotactic body radiotherapy (SBRT) (n = 12). The 2-year FFP and OS rates among this cohort were 84.4% and 63.6%, respectively. The 2-year OS rates for platinum-sensitive disease vs platinum-resistant disease were 65.2% and 35.7%, respectively (P = .02). Predictors of decreased FFP included a diagnosis of primary peritoneal carcinoma (P = .02) and time to RT < 12 months (P = .03). RT was well tolerated, with the majority of patients reporting no acute effects (56%) or developing mild symptoms, such as grade 1 gastrointestinal or urinary toxicity (19%). Late toxicity consisting of small bowel obstruction occurred in seven patients with other risk factors, including previous surgical resections; five (71%) of these patients had received whole-abdominopelvic radiation. For patients with metastatic ovarian cancer treated with palliative intent, the median dose of RT was 30 Gy (range: 10–50.4 Gy), delivered using 3D conformal RT (n = 44) and IMRT/stereotactic radiosurgery (SRS) (n = 17). Symptom palliation was achieved in 96% of cases. Reports of toxicity were low for this cohort of patients, with no grade ≥ 3 toxicity. The 2-year OS for patients treated with palliative intent was 53.8%.

CONCLUSIONS: The use of RT for primary or recurrent ovarian cancer is well tolerated, with durable rates of FFP. RT with palliative intent achieved high rates of symptom palliation without much additional toxicity. RT should be considered for patients with advanced ovarian cancer.

Proceedings of the 97th Annual Meeting of the American Radium Society- americanradiumsociety.org