Leveraging technology and standardized institutional practices to mitigate disparities in breast cancer radiation...

Disparities in various dimensions, including racial, in breast cancer treatment and outcomes are well established. A recent multi-institutional study reported a higher mean heart dose (MHD) in Black and minority women compared to White women who underwent left-sided breast/chest wall irradiation which translated into excess cardiac events and mortality. We evaluated the MHD of women treated in our institution and investigated whether institution-wide measures including the use of readily available but inconsistently adopted technologies can mitigate this disparity.

We identified 509 female patients treated with left-sided breast/chest wall irradiation with/without regional nodal irradiation (RNI). Details regarding cardiac dosimetry, deep-inspiratory breath-hold (DIBH) such as active breathing coordinator (ABC) use, breast size, internal mammary nodal (IMN) irradiation, and whether the treatment plan met boarding pass requirements and was peer reviewed were noted. MHD differences across racial groups were analyzed using Kruskal-Wallis test, while UVA and MVA linear regression analyses assessed influence of various factors on MHD.

MHD(Gy) was similar across racial groups; 1.38, 1.35, and 1.39 (p = 0.6) in Black, White, and other racial groups, respectively. Utilization of hypofractionation, cavity boosts, RNI, IMN irradiation, meeting boarding pass requirements, and peer review were similar. ABC usage (%) was 83/75/62 (p = 0.005), while median breast size(cc) was 1504/1904/1331 (p = 0.001) in White/Black/other women, respectively. On UVA and MVA, MHD differed with IMN treatment, boost and ABC use but not racial groups and varying breast sizes.

Despite anatomical differences such as breast size, achieving similar cardiac dose is feasible across racial groups by uniformly utilizing appropriate technology such as ABC, with standardized boarding pass constraints, and peer review of all cases. Further studies to identify factors that may cause varied cardiac morbidity rates despite similar cardiac dosimetry among racial groups are warranted.