Pathologic findings and clinical outcomes in women undergoing risk-reducing surgery to prevent ovarian and fallopian tube carcinoma: A large prospective single institution experience.

Risk-reducing salpingo-oophorectomy (RRSO) is recommended for women at increased risk of ovarian, fallopian tube (FT), and peritoneal carcinoma (collectively OC). We describe rates of occult neoplasia in the largest single-institution prospective cohort of women undergoing RRSO, including those with mutations in non-BRCA homologous repair (HRR) genes. Participants undergoing RRSO enrolled in a prospective tissue bank between 1999 and 2017. Ovaries and FTs were serially sectioned in all cases. Participants had OC susceptibility gene mutations or a family history suggesting OC risk. Analyses were completed in Stata IC 15.1. Of 644 women, 194 (30.1%) had mutations in BRCA1, 177 (27.5%) BRCA2, 27 (4.2%) other HRR genes, and 15 (2.3%) Lynch Syndrome-associated genes. Seventeen (2.6%) had occult neoplasms at RRSO, 15/17 (88.2%) in the FT. Of BRCA1 carriers, 14/194 (7.2%) had occult neoplasia, 8/194 (4.1%) invasive. One PALB2 and two BRCA2 carriers had intraepithelial FT neoplasms. Occult neoplasm occurred more frequently in BRCA1/2 carriers ≥45 years of age (6.5% vs 2.2%, chi square, p = .04), and 211/371 (56.9%) BRCA1/2 carriers had surgery after guideline-recommended ages. Four in 8 (50%) invasive and 2/9 (22%) intraepithelial neoplasms had positive pelvic washings. None with intraepithelial neoplasms developed recurrence or peritoneal carcinoma. BRCA1 carriers have the highest risk of occult neoplasia at RRSO, and the frequency increased with age. Women with BRCA1/2 mutations often have RRSO beyond recommended ages. One PALB2 carrier had FT intraepithelial neoplasia, a novel finding. Serial sectioning is critical to identifying occult neoplasia and should be performed for all risk-reducing surgeries.