Abstract C038: First- and second-degree family history of ovarian and breast cancers in relation to risk of invasive ovarian cancer in African American and White women

Background: Family history of ovarian and breast cancers is a well-established risk factor for ovarian cancer and recent findings suggest that the risk of ovarian cancer may be higher for African American (AA) women compared to other racial/ethnic groups. Few studies have been able to examine this association in both AA and White participants taking into account histotype. Methods: The Ovarian Cancer in Women of African Ancestry Consortium harmonized data from four case-control studies and two case-control studies nested within cohort studies. Each study collected self-reported first-degree family history of ovarian and breast cancers; the four case-control studies also collected self-reported data on second-degree family history of ovarian and breast cancers. For cases, data on age at diagnosis, tumor grade, and tumor histology were abstracted from medical records and cancer registry reports. Race-specific odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multilevel logistic regression with control for covariates. Results: Our sample included 1,052 AA cases, 2,328 AA controls, 2,380 White cases, and 3,982 White controls. The prevalence of first-degree history of ovarian or breast cancer was higher among AA than White ovarian cancer cases (28% vs. 21%) and similar among AA and White controls (15% vs. 16%). The prevalence of second-degree family history of ovarian or breast cancer was similar among AA and White ovarian cancer cases (38% vs. 34%) and among AA and White controls (28% vs. 32%). First-degree family history of ovarian cancer was significantly associated with high-grade serous ovarian cancer in both AA (OR=2.33; 95% CI: 1.48, 3.69) and White participants (OR=2.86; 95% CI: 2.03, 4.02). In AA women, first-degree family history of breast cancer was associated with increased risk of high-grade serous ovarian cancer (OR=1.80; 95% CI: 1.38, 2.34) and all other histotypes combined (OR=1.62; 95% CI: 1.16, 2.25). In White women, first degree family history of breast cancer was associated with high-grade serous ovarian cancer only (OR=1.40; 95% CI: 1.16, 1.68). Second-degree family history of ovarian cancer was associated with high-grade serous ovarian cancer among White women (OR=1.95; 95% CI: 1.32, 2.90) and second-degree family history of breast cancer was associated with high-grade serous ovarian cancer in AA women (OR=1.48; 95% CI: 1.11, 1.98). Second-degree family history of ovarian or breast cancer was not associated with the other histotypes. Estimates across studies were compatible with overall estimates (pheterogeneity>0.05). Conclusion: First-degree family history of ovarian cancer may be more strongly associated with high-grade serous ovarian cancer than other histotypes in AA and White women. Second-degree family history of cancer may differ by race in the associations with ovarian cancer, but potential underreporting of second-degree family history and inability to account for family size limit interpretation of these data. Citation Format: Traci N. Bethea, Heather M. Ochs-Balcom, Elisa V. Bandera, Alicia Beeghly-Fadiel, Fabian Camancho, Emily K. Cloyd, Holly R. Harris, Charlotte E. Joslin, Evan Myers, Patricia G. Moorman, Lauren C. Peres, Veronica W. Setiawan, Anna H. Wu, Lynn Rosenberg, Joellen M. Schildkraut. First- and second-degree family history of ovarian and breast cancers in relation to risk of invasive ovarian cancer in African American and White women [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C038.