Radiotherapy in recurrent ovarian cancer: updated results of involved-field radiation therapy

This study aimed to update the possible clinical benefits of radiation therapy in recurrent ovarian cancer.The medical records of 495 patients with recurrent ovarian cancer after initially undergoing maximal cytoreductive surgery and adjuvant platinum-based chemotherapy based on the pathologic stage between January 2010 and December 2020 were analyzed: 309 and 186 patients were treated without and with involved-field radiation therapy, respectively. Involved-field radiation therapy is defined as radiation therapy only to the areas of the body involved by tumor. The prescribed doses were ≥45 Gy (equivalent dose in 2 Gy/fraction). Overall survival was compared between patients treated with and without involved-field radiation therapy. The favorable group was defined as patients who satisfied at least four of the following factors: good performance, no ascites, normal CA-125, platinum-sensitive tumor, and nodal recurrence.The median age of the patients was 56 years (range 49-63) and median time to recurrence was 11.1 months (range 6.1-15.5). 217 patients (43.8%) were treated at a single site. Radiation therapy, performance status, CA-125, platinum sensitivity, residual disease, and ascites were all significant prognostic factors. The 3-year overall survival of all patients, patients treated without radiation therapy, and patients treated with radiation therapy was 54.0%, 44.8%, and 69.3%, respectively. Radiation therapy was associated with higher overall survival rates in the unfavorable and favorable patient groups. Patient characteristics showed higher rates of normal CA-125, lymph node metastasis only, lower platinum sensitivity, and higher rates of ascites in the radiation therapy group. After propensity score matching, the radiation therapy group showed superior overall survival to the non-radiation therapy group. Normal CA-125, good performance status, and platinum sensitivity were associated with a good prognosis in patients treated with radiation therapy.Our study showed that higher overall survival was observed in patients treated with radiation therapy in recurrent ovarian cancer.