A Comprehensive Evaluation Of Breast Cancer Treatment Delays By Race Among Women'S Health Initiative Participants.

e18579 Background: Breast cancer (BC) mortality is higher in Black vs White women, attributed in some studies to treatment delay. However, prior studies evaluated delay to initial treatment, leaving the role of delay to subsequent therapy uncertain. Therefore, we investigated delays across the treatment spectrum. Methods: We included women from the Women’s Health Initiative (WHI) who were diagnosed with BC (stage I-III) at age 65+ years. In this prospective analysis of 3466 incident BC, we used Medicare claims to characterize treatment. Delays were categorized (yes/no) across surgery, chemotherapy, and radiation as > 8 weeks from diagnosis or prior treatment to initiation of subsequent treatment. Results: Among BC cases, 188 were non-Hispanic black, 3129 were non-Hispanic white; 358 were HER2+, 266 were triple negative. In comparison to white women, a higher percent of black women had delay to chemotherapy (9.0% vs 3.9%; P < 0.001) and a marginally higher percent had surgery delay (13.3% vs 9.1%; P = 0.05), but had similar delays to radiation (12.2% vs 14.0%; P = 0.50). Delay to chemotherapy was associated with an increased risk of BC-specific mortality (HR = 1.7 [1.1-2.6]), but delay to surgery and radiation were not. Treatment delays did not alter the risk of BC-specific mortality associated with race. Conclusions: Our results confirm prior findings that black women with BC are more likely to have chemotherapy delays vs white women, and suggest that black women were more likely to have surgery delays. Our findings suggest that despite the greater risk of mortality associated with chemotherapy delay, this delay did not contribute to the increased risk of BC mortality in black vs white BC cases. N Breast cancer death Mean followup (y) Hazard Ratio* lower CL upper CL Delay to surgery No 3143 199 9.82 1.0 Yes 323 14 8.08 0.80 (0.46, 1.39) Delay to chemotherapy No 3317 184 9.64 1.0 Yes 149 29 9.99 1.70 (1.13, 2.57) Delay to radiation No 2981 177 9.72 1.0 . Yes 485 36 9.27 1.27 (0.89, 1.83) Cumulative delays 0 2584 144 9.87 1.0 1 808 60 9.13 1.24 (0.91, 1.67) 2-3 74 < 11 8.18 1.50 (0.76, 2.98) *Adjusted for a priori confounders: age at diagnosis, tumor size, nodal involvement, ER+, PR+, Her2+, Charlson comorbidity score