292 Efficacy of RRSO in BRCA carriers and clinical outcomes of follow-up in patients with isolated STIC

Introduction/Background* Serous Tubal Intraepithelial Carcinoma (STIC) is a non-invasive subtype of high-grade serous carcinoma (HGSC), usually located at the tubo-peritoneal junction and currently considered the precursor lesion of HGSC. The management of STIC diagnosed after Risk-Reducing Salpingo-Oophorectomy (RRSO) in women with BRCA-carriers remains unclear. The aim of our study was to evaluate the incidence of STIC, serous tubal intraepithelial lesions (STIL) and Occult-Cancer (OC) in patients submitted to RRSO and determine the long-term outcomes of these patients. Methodology We conducted an observational retrospective study on patients with BRCA 1-2 mutation who undergone RRSO between January-2010 to Dicember-2020 at the Gynaecology Clinic of Padua. Inclusion criteria: (i) women with a negative pelvic examination prior to RRSO (ii) fallopian tubes analyzed using the Sectioning and Extensively Examining the Fimbriated (SEE-FIM) protocol. Exclusion criteria: patients with a positive gynecologic screening or with ovarian/tubal cancer prior to RRSO. We collected data about age, menopausal status, history of breast carcinoma, pre-operative CA-125 levels, transvaginal-ultrasound features before surgery, and follow up (FUP) information after RRSO, specifically with CA-125 and gynecologic examination. Result(s)* We included 153 patients: baseline characteristics (table 1). STICs was diagnosed in 4 (2.6%) and STILs in 6 (3.9%) patients. None patients with STIC and STIL underwent a restaging surgery or adjuvant chemotherapy; all patients were followed closely every 6 months with transvaginal-ultrasound and CA-125. None of them developed peritoneal carcinoma (PC) or primary peritoneal carcinomas (PPC) with a median FUP of 54.5 months (15-106) and 57,5 months (12-82) in patients with STIC and STIL, respectively. OC was diagnosed in 3 patients (2%) and they underwent a staging-surgery; one patient developed a recurrence with PC after 18 months by staging surgery. Conclusion* Considering the low incidence of OC-STIC-STIL, our data support the importance of RRSO in patients with BRCA 1-2 mutations for reducing the risk of ovarian cancer and for detecting the lesions in early stage. The management of patients with isolated STIC that is aimed to decreases the rates of subsequent PPC and PC. Our results demonstrated that a long-term close surveillance in patients with STIC should be considered a possible management strategy.