Occult neoplasia in risk-reducing bilateral salpingo-oophorectomy: Pathological findings and clinical implications.

Abstract

e22558 Background: RRSO is a well-established risk-reducing strategy for ovarian and fallopian tube cancer in genetically high-risk women, particularly BRCA1/2 carriers. With increasing recognition of the fallopian tube as the site of origin of high-grade serous carcinoma, detailed pathological evaluation has become critical to identify occult malignancies and precursor lesions such as serous tubal intraepithelial carcinoma (STIC). We aimed to evaluate the prevalence of occult neoplasia and clinical outcomes in high-risk women undergoing RRSO at a tertiary cancer center. Methods: We conducted a retrospective cohort study of consecutive high-risk women who underwent RRSO between 2020 and 2024 at A.C. Camargo Cancer Center. Clinical characteristics, germline genetic results, surgical details, pathological findings, peritoneal cytology, and oncologic outcomes were reviewed. High-risk status was defined by the presence of pathogenic germline variants and/or strong family history of cancer. Pathological evaluation followed institutional protocols for detailed examination of ovaries and fallopian tubes. Results: A total of 232 risk-reducing surgeries were performed; 225 patients (96.9%) underwent bilateral salpingo-oophorectomy and 7 (3.0%) salpingectomy alone. Median age at surgery was 48.9 years. Most patients had a prior diagnosis of breast cancer (n = 166, 71.5%), while 20% underwent surgery based solely on presymptomatic genetic counseling and family history. Germline testing revealed pathogenic variants predominantly in BRCA1 (n = 98, 42.2%) and BRCA2 (n = 76, 32.7%), followed by mismatch repair genes (n = 17, 7.3%), PALB2 (n = 13, 5.6%), RAD51C (n = 7, 3.0%), RAD51D (n = 5, 2.1%), and other genes (n = 16, 6.8%). Peritoneal lavage was performed in 139 patients (59.9%), with malignant cells identified in 3 cases (2.2%). Pathological examination demonstrated benign ovarian and tubal findings in 228 patients (98.3%). Occult neoplastic lesions were identified in 4 patients (1.7%): one invasive high-grade serous ovarian carcinoma (FIGO stage IIIC) associated with STIC, two isolated STIC lesions, and one ovarian metastasis from breast cancer. After a median follow-up of 69 months, overall survival was high, with only two deaths reported. No subsequent primary gynecologic cancers were diagnosed. Cancer recurrence occurred in four patients with prior breast cancer and in one patient with melanoma. Conclusions: In this large single-center cohort of high-risk women undergoing RRSO, occult intraepithelial or invasive malignancies were uncommon. Nevertheless, the detection of STIC and advanced ovarian cancer reinforces the importance of meticulous pathological assessment following risk-reducing surgery. These findings support the oncologic safety of RRSO while highlighting its diagnostic value in identifying clinically occult disease.