Risk stratification of abdominopelvic failure for FIGO stage III epithelial ovarian cancer patients: implications for adjuvant radiotherapy

OBJECTIVE To analyze patterns of abdominopelvic failures and to define subgroups for the use of adjuvant radiotherapy in the International Federation of Gynecology and Obstetrics (FIGO) stage III epithelial ovarian cancer (EOC). METHODS We reviewed 149 patients treated with debulking surgery followed by intravenous taxane and platinum chemotherapy between 1999 and 2008. Patient characteristics, patterns of failure, abdominopelvic failure APF-free survival (APFFS) and overall survival (OS) were analyzed. RESULTS The median age of the patients was 51 years. Thirty-two patients (21.5%) were found to have residuum >2 cm after surgery. The median pretreatment CA-125 was 604 and 54.4% of patients had a decline in CA-125 ≥90% between pretreatment and at postoperative 1 month. With a median follow-up of 50 months, 79 patients (53.0%) experienced abdominopelvic failure (APF). The 5-year APF-free survival rate was 41.1%. Lymph node metastasis, size of residual disease, and decline in CA-125 were found to be significant prognostic factors for APF upon multivariate analysis. The group of patients in whom abdominopelvic irradiation was indicated as definitive postoperative treatment comprised 55% of the overall patient population and their 5-year survival rate was 68%. CONCLUSION The stratification was suggested to predict APF based on lymph node metastasis, size of residual tumor, and decline in CA-125. Adjuvant radiotherapy covering the whole abdominopelvis using the intensity modulation technique may be considered to reduce APF in FIGO stage III EOC patients with intermediate risk.