Peritoneal cancer risk after risk reducing salpingo-oophorectomy, impact of mutational status and STIC lesions.

Women with inherited susceptibility or a strong family history of ovarian cancer, particularly carriers of pathogenic BRCA1/2 variants, face a markedly increased lifetime risk. To mitigate this risk, current guidelines recommend risk-reducing salpingo-oophorectomy (RRSO) between ages 35 and 40 for BRCA1 and between ages 40 and 45 for BRCA2 METHODS: We conducted an ambispective multicenter study in France including 1351 women at high risk of ovarian cancer, 984 of whom carried BRCA1/2 pathogenic variants, totaling 7433.3 woman-years of follow-up. When histological reports from RRSO revealed abnormalities, surgical specimens were reviewed, with special focus on the fallopian tubes to identify serous tubal intraepithelial carcinoma (STIC). The incidence of peritoneal carcinoma (PC) after RRSO was recorded. STIC was detected in 14 patients at RRSO (10 BRCA1; 2 BRCA2 carriers). During follow-up, 4 women developed PC, corresponding to a 5-years cumulative incidence of 0.4% in the overall cohort and 0.5% among BRCA1/2 carriers. Age at surgery was significantly associated with pathological findings: invasive carcinoma was detected at a median age of 55 years, STIC at 54 years, and benign lesions at 51 years (p < 0.001). Notably, women with STIC at RRSO had a 5-year PC risk of 11.1%. These findings highlight the importance of early RRSO, meticulous tubal evaluation, and extended post-surgical surveillance in genetically at-risk women. Detection of STIC warrants tailored follow-up strategies. Further studies are needed to assess the effectiveness and morbidity of staging surgery or regular monitoring using CA125 or innovative markers such as ctDNA.