Mediators of Racial Disparities in Heart Dose Among Whole Breast Radiotherapy Patients

Area of Science:

• Oncology
• Radiotherapy
• Cardiovascular Health

Background:

• Racial disparities in cancer survival necessitate research into treatment inequities.
• Previous studies have not assessed cardiac radiation dose by race in large breast cancer cohorts.
• Understanding dose disparities and their implications is critical for patient outcomes.

Purpose of the Study:

• To quantify racial disparities in cardiac radiation dose among breast cancer patients.
• To evaluate the multilevel determinants contributing to these disparities.
• To estimate the impact of cardiac dose disparities on ischemic cardiac events and mortality.

Main Methods:

• Analysis of a statewide consortium database of 8750 women undergoing whole breast radiotherapy (2012-2018).
• Development of laterality- and fractionation-specific models for mean heart dose.
• Patient- and facility-level modeling to estimate race-specific cardiac doses and associated risks.

Main Results:

• Black and Asian women showed independently higher mean heart doses compared to White women.
• Disparities reached up to 0.42 Gy for Black women and 0.32 Gy for Asian women.
• These dose differences correlated with estimated excess cardiac events and deaths per 1000 women.

Conclusions:

• Breast cancer patients of Black and Asian race receive higher cardiac radiation doses than White patients.
• These higher doses may lead to an increased risk of radiation-associated ischemic cardiac events and mortality.
• Addressing baseline cardiac risk factors and improving access to advanced radiation technologies are potential solutions.