Abstract 2314: Prevalence and risk factors for occult tubal and ovarian cancer at the time of benign gynecologic surgery in the general population: A nationwide analysis of privately insured women

Abstract

Abstract Background: Compelling molecular and pathological evidence demonstrating early invasive cancers in the fallopian tubes of BRCA1/2 carriers at the time of prophylactic surgery support the hypothesis that fallopian tube cancers are precursors of high-grade serous ovarian cancer. These findings have led to a rapid increase in opportunistic salpingectomy (OS) for ovarian cancer prevention among women in the general population. However, little data exists on the prevalence and risk factors for occult cancer in the general population. Methods: We identified all benign gynecologic surgeries (hysterectomy, bilateral salpingo-oophorectomy [BSO], OS, tubal ligation [TL]) among 45 million women aged 18-64 years from the Truven Health Analytics MarketScan Commercial Claims and Encounters Database between 2010 and 2017. Among the 557,693 women identified, we evaluated the prevalence and risk factors for tubal, ovarian, and peritoneal cancers at the time of surgery using log-binomial regression. Additionally, we examined the incidence of subsequent peritoneal cancer after BSO using Poisson regression. All models were adjusted for age, type of surgery, geographic region, rural/urban location, type of insurance, family history of breast and/or ovarian cancer, BRCA1/2 testing, and Charlson comorbidity index. Results: The most common indications for surgery were sterilization (34%), menstrual disorders (17%), and uterine fibroids (15%). A total of 192 occult cancers (149 ovarian, 22 fallopian tube, 21 peritoneal) were diagnosed at surgery. The median age at occult cancer diagnosis was 51 years (IQR: 44-57 years), and the age-adjusted prevalence was 0.035% (95% CI: 0.031-0.039) overall and 0.027% (95% CI: 0.023-0.032) excluding women with a family history of breast and/or ovarian cancer. Age-adjusted prevalence of occult cancer was highest in women with hysterectomy and BSO (0.113%; 95% CI: 0.084-0.144) followed by OS (0.047%, 95% CI: 0.005-0.089). Prevalence was similar for women with hysterectomy (0.027%, 95% CI: 0.020-0.033) and hysterectomy and OS (0.027%, 95% CI: 0.005-0.048) while women with TL had the lowest prevalence of occult cancer (0.007%, 95% CI: 0.003-0.011). In adjusted analyses, older age (prevalence ratio (PR) 40-54 years: 2.94, 95% CI: 1.81-4.79 vs <40 years; PR ≥55 years: 14.66, 95% CI: 8.35-25.74 vs <40 years), family history of breast and/or ovarian cancer (PR breast or ovarian cancer: 2.82, 95% CI: 2.01-3.97 vs none; PR breast and ovarian cancer: 10.62, 95% CI: 4.53-24.90 vs none), and number of comorbidities (PR 1+ comorbidities: 1.86, 95% CI: 1.19-2.88 vs 0 comorbidities) were significantly associated with occult cancer diagnosis. No women developed subsequent peritoneal cancer after an average follow-up of 2.2 years. Conclusions: In this large nationwide sample of women undergoing benign gynecologic surgery, occult cancers developed >10 years before the median age at which women are diagnosed with ovarian cancer. The prevalence of occult cancer was significantly lower than the prevalence reported by prior studies in selected BRCA1/2 carriers (2.5%-5.0%) and non-carriers (0.5%) undergoing prophylactic surgery. We also identified pre-surgical comorbidities as a novel risk factor for occult cancer. Citation Format: Pritesh S. Karia, Corinne E. Joshu, Kala Visvanathan. Prevalence and risk factors for occult tubal and ovarian cancer at the time of benign gynecologic surgery in the general population: A nationwide analysis of privately insured women [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2314.