ASPO Abstracts

Estimation of contributing factors to racial disparities in epithelial ovarian cancer survival

Authors: Harris HR, Camacho TF, Johnson C, Wu AH, Moorman PG, Myers E, Bethea TN, Bandera EV, Joslin CE, Ochs-Balcom HM, Peres LC, Guertin KA, Rosenow WT, Setiawan VW, Beeghly-Fadiel A, Dempsey L, Rosenberg L, Schildkraut J

Category: Cancer Health Disparities
Conference Year: 2021

Abstract Body:
Purpose of Study: Using multiple mediation analysis we sought to determine why African- American women have poorer ovarian cancer survival compared to White women. Methods: We examined data from the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium which harmonized questionnaire-based data on 1,075 African-American women and 3,272 White women with ovarian cancer from seven U.S. studies. We first selected potential mediators and confounders by examining the associations between each variable and both race and survival and then incorporated these variables into a sequential multiple mediation analysis. We used multiple imputation and bootstrapping to fit and pool natural effects models with counterfactual exposures and survival times. In order to distinguish the effect of race through mediators and otherwise, we implemented log-normal accelerated failure time and Cox proportional hazards models. Results: In OCWAA, 67.8% (n=729) of African-American women and 69.7% (n=2,282) of White women were deceased. The hazard ratio for African-American women compared to White women was 1.29 (95% CI=1.15-1.46). In our final model, mediators of this disparity in survival included college education, nulliparity, smoking status, body mass index, diabetes, diabetes/race interaction, postmenopausal hormone (PMH) therapy duration, PMH duration/race interaction, PMH duration/age interaction, histotype, and stage. These mediators explained 46.4% (95% CI=30.9-60.0%) of the overall racial disparity in ovarian cancer survival, and histotype/stage and PMH duration accounted for the largest fraction. Conclusions: Nearly half of the disparity in ovarian cancer survival between African-American and White women is explained by education, lifestyle factors, diabetes, PMH use, and tumor characteristics. Our findings suggest a role of several potentially modifiable factors in ovarian cancer survival disparities. Further research to uncover additional mediators and potential avenues of intervention to reduce this disparity is warranted.

Keywords: racial disparities, ovarian cancer, survival