796P Initial management and long-term outcome of advanced low-grade serous ovarian cancer (LGSOC) exploring role of surgery and maintenance therapy in the French multicentre ESME database

LGSOC is a rare disease. Few data of large size have been published. We conducted a multicenter retrospective analysis of LGSC patients selected from the French Epidemiological Strategy and Medical Economics Ovarian Cancer database between 2000 and 2019. This database includes all ovarian cancer pts treated in 18 French Comprehensive Cancer Centers. The main objective was to describe the management of these patients. Secondary objectives were to analyse progression-free survival (PFS) and overall survival (OS) and prognostic factors in the stage III/IV population. Out of the 13032 pts, 230 (1.8%) with a confirmed diagnosis of stage III (n=171)/IV (n=59) LGSOC were identified. Median age at diagnosis was 55.5y (19.8-88.2). 128 (55.6%) pts had primary debulking surgery (PDS) and 35 (15.2%) neoadjuvant chemotherapy (NACT) and interval debulking surgery (IDS). 49 (21.3%) pts did not have debulking surgery and 18 (7.9%) patients had surgery after 6 courses of NACT. 223 pts (97.0%) received platinum-based chemotherapy (PBC) including bevacizumab (Bev) for 79 pts (34.3%). Endocrine therapy maintenance was given in 27 pts. After a median follow up of 73.6m [69.9-80.0], median OS was 93.4m (95%CI [71.2-176.9]) in the whole population. Median OS according to timing of surgery was 146.0m (95%CI [110.4-NR]) with PDS vs. 75.5m (95%CI [48.7-Not Reached]) with NACT-IDS vs. 61.8m (95%CI [42.4-NR]) with 6 courses of NACT and closing surgery. Patients not candidate for surgery received PBC (n=49) +/-Bev (14/49) +/- maintenance endocrine therapy (13/49). With a median follow-up of 64.6m (38.6-93.6), median PFS and OS were 15.9m (95%CI [13.4-20.6]) and 38.0 m (95%CI [33.0-65.0]) respectively. OS multivariable analyses are shown in the table. Table: 796PHR95%CIp valueInitial FIGO stageIIIIV2.401.48,3.91<0.001Timing of surgeryPrimary debulking surgeryInterval debulking surgery or closing surgery1.931.13, 3.340.018No surgery2.651.50;4.68<0.001Age (continuous variable)1.011.00, 1.030.038Bevacizumab first lineNoYes0.820.51, 1.300.393 Open table in a new tab . In this large size population of advanced LGSOC, FIGO IV stage, absence of PDS and age are associated with poorer OS.