Role of salvage radiotherapy for recurrent ovarian cancer.

OBJECTIVE: This study aimed to report clinical outcomes of salvage radiotherapy for recurrent ovarian cancer and identify predictors of clinical outcomes. METHODS: We retrospectively reviewed data of patients who received salvage radiotherapy for recurrent ovarian cancer between January 2011 and June 2021. Stereotactic body radiotherapy, involved-field radiotherapy with conventional fractionation, and non-involved-field radiotherapy with conventional fractionation were included in this study. Local failure-free survival, progression-free survival, chemotherapy-free survival, and overall survival were assessed. Additionally, potential prognostic factors for survival were analyzed. RESULTS: A total of 79 patients were included with 114 recurrent lesions. The median follow-up was 18.3 months (range 1.7-83). The 2-year local failure-free survival, progression-free survival, chemotherapy-free survival, and overall survival rates were 80.7%, 10.6%, 21.2%, and 74.7%, respectively. Pre-radiotherapy platinum resistance (hazard ratio (HR) 3.326, p<0.001) and short pre-radiotherapy CA-125 doubling time (HR 3.664, p<0.001) were associated with poor chemotherapy-free survival. The 1-year chemotherapy-free survival rates of patients with both risk factors, a single risk factor, and no risk factor were 0%, 20.4%, and 53.5%, respectively. The difference between risk groups was statistically significant: low risk versus intermediate risk (p<0.001) and intermediate risk versus high risk (p<0.001). CONCLUSIONS: Salvage radiotherapy for recurrent ovarian cancer resulted in local control with improved chemotherapy-free survival in carefully selected patients. Our results suggest that the consideration of pre-radiotherapy platinum resistance and pre-radiotherapy CA-125 doubling time could help with patient selection.