Outcome of African American (AA) compared to white American (WA) patients with early-stage breast cancer, stratified by phenotype
Lehrberg A, Nathanson D, Baidoun F, Petersen L, Susick L, Davis M, Ivanics T, Rakitin I, Bensenhaver J, Proctor E, and Newman L. Outcome of African American (AA) compared to white American (WA) patients with early-stage breast cancer, stratified by phenotype. Ann Surg Oncol 2018; 25(1 Suppl):S87.
Ann Surg Oncol
INTRODUCTION: Population-based breast cancer mortality rates are approximately 40% higher for AA compared to WA women. The extent to which these outcome disparities are related to the two-fold higher incidence of triple negative breast cancer (TNBC) in AAs is unclear. Methods: We evaluated survival among AA and WA pts presenting with clinically early-stage/node negative breast cancer, stratified by having TNBC versus non-TNBC phenotype from a prospectively-maintained, IRB-approved database in an employee health plan-based hospital system serving a diverse community; Median follow-up was 60 months. Results: A total of 2,847 cases were analyzed; 1,061 (37%) AA and 1,786 (63%) WA. Frequency of TNBC was higher among the AA patients compared to WA patients (15% versus 10%; p<0.05) and frequency of non-TNBC/HER2-negative disease was lower among AA compared to WA patients (53% versus 62%; p<0.05). Median survival of AA compared to WA pts was shorter (median survival 1175 versus 1691 days; Wilcoxon p-value 0.002), but median survival of AA and WA TNBC pts was not statistically different (1094 versus 1636 days; p-value 0.397). Outcome disparities re-emerged for AA compared to WA pts with HER2-positive/non-TNBC (median survival 1210 versus 1717 days; p-value 0.015), and for HER2-negative/non-TNBC (median survival 1722 versus 2088 days; p-value 0.10) although the difference was not statistically significant for the latter. Conclusions: Variation in TNBC prevalence likely contributes to race-associated breast cancer disparities overall, but outcome differences associated with HER2-positive and hormone receptor-positive disease suggest that variations in delivery of targeted therapy or response to targeted therapy may also be playing a role.