Clinical features of long-term survivors with advanced high-grade serous ovarian cancer.

e17575 Background: Most patients diagnosed with high-grade serous ovarian cancer (HGSOC) at advanced stages (FIGO III&IV) have limited survival. However, approximately 30% of patients survive more than 5 years, some of them without relapse. A better understanding of these patients may uncover novel factors contributing to their long survival beyond those known to be related to HGSOC prognosis (age, stage and residual disease after surgery). This descriptive study aims to analyze the clinical characteristics of these exceptional survivors and describe them in contrast to patients with worse survival in a cohort of patients diagnosed before the introduction of PARP inhibitors as first-line maintenance therapy. Methods: A descriptive analysis of patients newly diagnosed with advanced HGSOC at our University Hospital between 2009 and 2018 was conducted. We report clinical characteristics of long-term survivors (LTS), defined as patients alive after 5 years(y) from the date of diagnosis and characteristics of patients who survived less than two years from the date of diagnosis, classified as short- term survivors (STS). Results: Among 195 patients with advanced HGSOC 42 (21,5%) survived less than 2y and 48 (24,6%) more than 5y, 18 of them (37,5%) without relapse. The Median age was 61.1y for LTS and 64.8 for STS. In the LTS group, 77.1% of patients were stage III, and 22.9% were stage IV. In the STS group, the distribution of patients with stage III and IV was 42.9% and 57.1%, respectively. A higher proportion of LTS underwent surgery n=44 (91,7%), most of them as interval debulking surgery (59.1%). Almost half of STS did not undergo surgery (45,2%), being interval debulking surgery the most frequent systematic approach when surgery was performed (73.9%). Only 9,1% of LTS who underwent surgery had residual disease compared to 27,3% of STS. Harboring mutations in the BRCA1/2 genes is a favorable prognostic factor also associated with chemotherapy sensitivity, in our serires 23% of LTS were BRCA1&2 mutation carriers (11 patients (23%) patients with germline BRCA mutations being 7patients(15%) BRCA1mut and 4patients(8%) BRCA2mut with 4patients(8%) of patients not analyzed). Conclusions: In our cohort, stage III and cytoreduction surgery were more frequent among LTS. Classical clinical characteristics are not enough to identify advanced HGSOC LTS. More investigation on their molecular profile might help to to identify exceptional LTS in order to elucidate better management approaches and new treatments for patients with worse prognosis.