969PD - Natural History of Serous Ovarian Carcinoma: High Grade Versus Low Grade and Carcinomas with BRCA Mutations

Abstract

ABSTRACT Serous carcinomas are the commonest histological subtype of epithelial ovarian cancer (EOC) and associated with BRCA mutations. In this study we analysed presentation and treatment-related outcomes of patients with high-grade(HGSC) and low-grade serous carcinomas (LGSC) and their relationship with BRCA mutations. Study design A retrospective cohort study was carried out. Patients diagnosed with serous ovarian carcinoma from 2005-2010 were identified. A separate database was accessed to identify BRCA carriers ever treated at the Christie Hospital, UK. Individual patient data was analysed. Results 391 patients were identified including 151 with BRCA mutations. Preliminary data on 303 cases is discussed. Mature data will be presented at the meeting. The prevalence of LGSC is low. They present a decade earlier than HGSC (median age 50 vs 64) and fewer patients have advanced disease at first presentation (50%). The relapse rate is significantly less than with HGSC (23% vs 64%). Fewer patients with LGSC maintained platinum-sensitivity at first (15% vs 45%) and subsequent relapse (4% vs 20%). The median age of ovarian cancer patients with BRCA mutations was 54. 66% were BRCA1 carriers. The predominant histological subtype was serous (50%). 25% were poorly differentiated carcinomas. 53% had FIGO III/IV disease at presentation. At the time of analysis over half of patients with BRCA mutations and HGSC had died compared to 30% with LGSC. BRCA carriers maintained platinum-sensitivity for a greater period of time and lived longer compared to patients with sporadic HGSC or LGSC. The median times to development of platinum-resistance for BRCA carriers, HGSC and LGSC were 139, 79 and 113 weeks respectively. The median overall survival times for the three groups were 367, 159 and 182 weeks respectively. BRCA2 carriers did better than BRCA1 patients. None of the LGSC were associated with BRCA mutations. Conclusion The presentation and natural history of LGSC is distinct to that of HGSC. BRCA carriers present at an earlier age and have better survival outcomes when compared to patients with sporadic serous ovarian carcinoma. Disclosure All authors have declared no conflicts of interest.