Risks of Second Primary Gynecologic Cancers Following Ovarian Cancer Treatment in Asian Ethnic Subgroups in the United States, 2000-2016.

BACKGROUND The differential occurrence of second primary cancers by race following ovarian cancer is poorly understood. Our objective was to determine the incidence of second primary gynecologic cancers (SPGC) following definitive therapy for ovarian cancer. Specifically, we aimed to determine differences in SPGC incidence by Asian ethnic subgroups. METHODS We identified 27,602 women ages 20 years and older and diagnosed with first primary epithelial ovarian cancer between 2000 and 2016 who received surgery and chemotherapy in 18 population-based Surveillance, Epidemiology and End Results Program registries. We compared the incidence of SPGC with expected incidence rates in the general population of women using estimated standardized incidence ratios (SIR) and 95% confidence intervals (CI). RESULTS The incidence of SPGC was lower among White women (SIR = 0.73; 95% CI, 0.59-0.89), and higher among Black (SIR = 1.80; 95% CI, 0.96-3.08) and Asian/Pacific Islander (API) women (SIR = 1.83; 95% CI, 1.07-2.93). Increased risk of vaginal cancers was observed among all women, although risk estimates were highest among API women (SIR = 26.76; 95% CI, 5.52-78.2) and were also significant for risk of uterine cancers (SIR = 2.53; 95% CI, 1.35-4.33). Among API women, only Filipinas had significantly increased incidence of SPGC overall including both uterine and vaginal cancers. CONCLUSIONS Risk of SPGC following treatment of ovarian cancer differs by race and ethnicity, with Filipina women having the highest rates of second gynecologic cancers among Asian women. IMPACT Ensuring access and adherence to surveillance may mitigate ethnic differences in the early detection and incidence of second gynecologic cancers.