Racial and Ethnic Differences in Long-Term Adverse Radiotherapy Effects among Breast Cancer Survivors.

PURPOSE: Breast and skin changes are an underrecognized side effect of radiotherapy for breast cancer, which may have long-term implications for quality of life (QOL). Racial and ethnic disparities in breast cancer outcomes including long-term QOL differences following breast radiotherapy are poorly understood.

METHODS AND MATERIALS: We conducted a cross-sectional survey study of patients from the XYZ Cancer Registry diagnosed with stage 0-II breast cancer from 2009-2014 and treated with lumpectomy and radiotherapy; 2,770 patients were sampled and 631 responded (23%). The BREAST-Q Adverse Effects of Radiation (AER) overall score and subindices measured the impact of radiotherapy on breast tissue. Multivariable logistic regression evaluated associations of demographic and treatment characteristics with outcomes.

RESULTS: The median age was 57 years (IQR 48-65), median time from diagnosis to survey response 9 years (IQR 7-10), and the cohort included 62 (9.8%) Asian American or Pacific Islander, 11 (1.7%) American Indian or Alaskan Native (AIAN), 161 (25.5%) Black, 144 (22.8%) Hispanic, and 253 (40.1%) White patients. Mean BREAST-Q AER score was worse for AIAN patients (-22.2, 95% CI -39.9 to -4.6, p=0.01), Black patients (-10.8, 95% CI -16.1 to -5.5, p<0.001), and Hispanic patients (-7.8, 95% CI -13.0 to -2.5, p=0.004) compared to White patients, age <50 compared to ≥65 (effect size -8.6, 95% CI -14.0 to -3.2, p=0.002), less than a college education (-5.8, 95% CI -10.0 to -1.6, p=0.01), bra cup size of D/E versus A/B (-5.3, 95% CI -9.9 to -0.65, p=0.03), and current smokers (-11.3, 95% CI -18.3 to -4.2, p=0.002). AIAN, Black, and Hispanic patients reported worse changes in skin pigmentation, telangiectasias, dryness, soreness, and/or irritation compared to White patients.

CONCLUSIONS: AIAN, Black, and Hispanic patients reported substantially worse long-term breast and skin QOL outcomes after radiotherapy. Additional work is needed to understand these differences and how to alleviate them.