Biological and non-biological predictors of breast cancer disease-free survival among young Black females
Presenting author: Run Fan, Department of Biostatistics, Vanderbilt University Medical Center
Young Black women bear a disproportionate burden of breast cancer (BC) mortality compared to White women. In a cohort of young African American women diagnosed with BC (n=687) we found that triple-negative status and lymph node involvement were associated with poorer disease-free survival (DFS) (p=0.027 and p=0.0003, respectively), while full-time employment showed with a strong protective effect (p<0.0001). Moreover, a higher percentage of West African ancestry was associated with worse DFS, with an interquartile hazard ratio of 1.23 (95% CI: 0.98-1.53, p=0.07). This association was even stronger in the hormone receptor-positive subgroup (n=323) (HR=1.56, 95% CI: 1.04-2.34, p=0.031). These results were based on a multivariable Cox regression model developed using a backward selection procedure. R package "radmixture" was used for the ancestry analysis, from which % West African was estimated and included in the multivariable analysis. Missing covariate data that could be reasonably assumed missing-at-random were imputed using multiple imputation with predictive mean match. Our findings confirmed previously identified predictors of poor BC prognosis, such as triple-negative status and lymph node involvement. Interestingly, full-time employment showed a significant protective effect among African American women with BC. Furthermore, we identified a novel association between West African ancestry and breast cancer prognosis.