Does serous tubal intraepithelial carcinoma (STIC) metastasize? The clonal relationship between STIC and subsequent high-grade serous carcinoma in BRCA1/2 mutation carriers several years after risk-reducing salpingo-oophorectomy.

The majority of high-grade serous carcinomas (HGSC) of the ovary, fallopian tube, and peritoneum arise from the precursor lesion called serous tubal intraepithelial carcinoma (STIC). It has been postulated that cells from STICs exfoliate into the peritoneal cavity and give rise to peritoneal HGSC several years later. While co-existent STICs and HGSCs have been reported to share similarities in their mutational profiles, clonal relationship between temporally distant STICs and HGSCs have been infrequently studied and the natural history of STICs remains poorly understood. We performed focused searches in two national databases from the Netherlands and identified a series of BRCA1/2 germline pathogenic variant (GPV) carriers (n = 7) who had STIC, and no detectable invasive carcinoma, at the time of their risk-reducing salpingo-oophorectomy (RRSO), and later developed peritoneal HGSC. The clonal relationship between these STICs and HGSCs was investigated by comparing their genetic mutational profile by performing next-generation targeted sequencing. Identical pathogenic mutations and loss of heterozygosity of TP53 were identified in the STICs and HGSCs of five of the seven patients (71%), confirming the clonal relationship of the lesions. Median interval for developing HGSC after RRSO was 59 months (range: 24-118 months). Our results indicate that cells from STIC can shed into the peritoneal cavity and give rise to HGSC after long lag periods in BRCA1/2 GPV carriers, and argues in favor of the hypothesis that STIC lesions may metastasize.

van den Berg CB ，Dasgupta S ，Ewing-Graham PC ，Bart J ，Bulten J ，Gaarenstroom KN ，de Hullu JA ，Mom CH ，Mourits MJE ，Steenbeek MP ，van Marion R ，van Beekhuizen HJ ... -  《-》

Retrospective study of a 16 year cohort of BRCA1 and BRCA2 carriers presenting for RRSO: Prevalence of invasive and in-situ carcinoma, with follow-up.

Carriers of BRCA1 and BRCA2 mutations are at increased risk of high grade serous carcinoma and are therefore offered risk-reducing salpingo-oophorectomy (RRSO) by 40-45 years. Most of these carcinomas are believed to arise in the fallopian tube from serous tubal intraepithelial carcinoma (STIC). We conducted a retrospective study on the prevalence of high grade serous carcinoma and STIC in BRCA1/2 carriers presenting for RRSO, and their follow-up. Consecutive BRCA1/2 carriers presenting for an RRSO at Erasmus MC (2000-2016) were studied. SEE-FIM pathology protocol was followed from 2010 onwards. For the cases with carcinoma and/or STIC, the histology was reviewed and immunohistochemistry (p53 & MIB-1) was performed. Next Generation Targeted Sequencing (NGTS) for TP53 mutation was used to establish clonality in 2 cases. Of the 527 included patients, 68% were BRCA1, 31.6% were BRCA2, and 0.4% carried both mutations. The prevalence of high grade serous carcinoma was 2.3% (12/527); 59% of these were of tubal origin. High grade serous carcinoma was more common in patients operated on after the recommended age (p = 0.03). Isolated STIC was present in 0.8% (4/527). Two BRCA1 carriers with isolated STIC at RRSO developed peritoneal serous carcinoma >7 years later. Identical TP53 mutations in the peritoneal serous carcinoma and the preceding STIC established their clonal origin. High grade serous carcinoma is more common in BRCA1/2 carriers presenting for RRSO after the recommended age, and is more often of tubal origin. Longer follow up of patients with STIC at RRSO should be considered.

Blok F ，Dasgupta S ，Dinjens WNM ，Roes EM ，van Beekhuizen HJ ，Ewing-Graham PC ... -  《-》

Efficacy of risk-reducing salpingo-oophorectomy in BRCA1-2 variants and clinical outcomes of follow-up in patients with isolated serous tubal intraepithelial carcinoma (STIC).

Serous tubal intraepithelial carcinoma (STIC) is currently considered the precursor lesion of pelvic high-grade serous carcinoma. The management of STIC diagnosed after risk-reducing salpingo-oophorectomy (RRSO) in women with BRCA1-2 variants remains unclear. The aim of our study was to evaluate the incidence of STIC, serous tubal intraepithelial lesions (STIL) and occult invasive cancer (OC) and to determine the long-term outcomes of these patients. We conducted a retrospective study of patients with BRCA 1-2 variants who underwent RRSO between January-2010 and Dicember-2020 at the Clinic of Gynaecology of University of Padova. women with a negative pelvic examination at the last screening prior to RRSO, patients with fallopian tubes analysed using the SEE-FIM protocol. patients with a positive gynaecologic screening or with ovarian/tubal cancer prior to RRSO. We included 153 patients. STICs were diagnosed in 4 patients (2.6%) and STILs in 6 patients (3.9%). None of the patients with STIC underwent restaging surgery or adjuvant chemotherapy; all patients were followed closely every 6 months. None of the patients developed primary peritoneal carcinomas (PPCs) with a median FUP of 54.5 months (15-106). OC was diagnosed in 3 patients (2%). All patients with OC underwent staging surgery, and one patient developed a peritoneal carcinoma (PC) after 18 months by staging surgery. The incidence of STIC, STIL and OC after RRSO in BRCA1-2 variants was low. Our results demonstrated that long-term close surveillance in patients diagnosed with STIC should be considered a possible management strategy.

Saccardi C ，Zovato S ，Spagnol G ，Bonaldo G ，Marchetti M ，Alessandrini L ，Tognazzo S ，Guerriero A ，Vitagliano A ，Laganà AS ，Noventa M ... -  《-》

Development of Peritoneal Carcinoma in women diagnosed with Serous Tubal Intraepithelial Carcinoma (STIC) following Risk-Reducing Salpingo-Oophorectomy (RRSO).

Stanciu PI ，Ind TEJ ，Barton DPJ ，Butler JB ，Vroobel KM ，Attygalle AD ，Nobbenhuis MAE ... -  《Journal of Ovarian Research》

Outcomes of Incidental Fallopian Tube High-Grade Serous Carcinoma and Serous Tubal Intraepithelial Carcinoma in Women at Low Risk of Hereditary Breast and Ovarian Cancer.

Chay WY ，McCluggage WG ，Lee CH ，Köbel M ，Irving J ，Millar J ，Gilks CB ，Tinker AV ... -  《-》