Socioeconomic and Racial Disparities in the Selection of Chest Wall Boost Radiation Therapy in Californian Women After Mastectomy

IntroductionHealthcare disparities in breast cancer treatment have been well documented. We investigated the socioeconomic status (SES) and racial factors in women with locally advanced breast cancer from the California Cancer Registry who had received postmastectomy radiation therapy (PMRT) with or without a chest wall boost (CWB).Patients and MethodsThe records of 4747 women with invasive breast cancer, diagnosed from 2005 to 2009, who had undergone PMRT, were reviewed and stratified by treatment with (n = 2686 [57%]) or without (n = 2061 [43%]) a CWB. Various patient demographic and biologic factors were analyzed using univariate and multivariate analysis.ResultsReceipt of a CWB was associated with race/ethnicity (P < .001), SES (P < .001), tumor size (P = .038), tumor grade (P = .033), human epidermal growth factor 2 (HER2) status (P = .015), American Joint Committee on Cancer stage (P = .001), number of nodes examined (P = .001), and number of positive nodes (P = .037) on univariate analysis. After controlling for confounding factors, race/ethnicity and SES remained independently predictive of a CWB. Hispanic women were more likely to receive a CWB than Asian (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.60-0.90), black (HR, 0.63; 95% CI, 0.48-0.83), or white (HR, 0.81; 95% CI, 0.69-0.95) women. Also, women of low SES were more likely to receive a CWB than women of high SES (HR, 0.74; 95% CI, 0.64-0.86).ConclusionWe found that poor and Hispanic women were more commonly treated with a CWB than were more affluent and non-Hispanic women with a similar cancer stage, cancer biology, and treatment paradigm.