Reducing Racial Disparities in Breast Cancer Treatment

Abstract

Racial disparities in breast cancer screening, treatment, and outcomes are well established. A recent multi-institutional paper showed a higher mean heart dose (MHD) in Black women and other minorities compared to White women who underwent left-sided breast or chest wall irradiation. We evaluated the MHD of women treated in our institution and investigated whether institution-wide measures can mitigate disparities. We identified 509 consecutively treated female patients from 2012 to 2021 who received left-sided breast or chest wall irradiation (with or without regional nodal irradiation). Medical records were queried to report cardiac dosimetry across various racial groups. Details regarding the use of active breathing control (ABC), breast size, internal mammary nodal irradiation, and whether the patient's treatment plan met the departmental boarding pass requirement and was prospectively presented at departmental peer review were noted. MHD were noted in absolute values and 2-Gy equivalent doses (EQD2). Kruskal-Wallis test was used to analyze differences in MHD between racial groups. Univariate and multivariable Cox regression analyses were performed to determine association of MHD with other factors. MHD was similar across racial groups; 1.38 Gy (1.12, 2.02) in Black women, 1.35 Gy (1.02, 1.97) in White women, and 1.39 Gy (1.07, 2.01) in others with an EQD2 of 0.71, 0.70 and 0.72 (P = 0.6). Rates of the use of hypofractionation, a cavity boost, regional nodal irradiation, internal mammary nodal irradiation, meeting departmental boarding pass requirement, and peer review of treatment plan before starting treatment were similar across all racial groups. The use of ABC was 83% in White women, 75% in Black women and 62% in other races (P = 0.005). The difference in ABC use was attributed to a higher rate of volumetric modulated arc therapy treatment in other races (33%). Median breast size was 1904 cc in Black women, 1504 cc in White women, and 1331 cc in other racial groups (P = 0.001). On univariate and multivariate analysis, MHD differed with IMN treatment, boost and use of ABC but remained similar across racial groups and varying breast size. Despite anatomical differences such as breast size, achieving similar cardiac dose is feasible across racial groups by uniformly utilizing ABC for left sided breast or chest wall irradiation, applying standardized boarding pass constraints and peer review of all cases. Further studies to identify factors that may lead to differences in the rates of cardiac morbidity among racial groups are warranted.