Assessing racial/ethnic disparities in chemotherapy treatment among breast cancer patients in context of changing treatment guidelines

Conflicting study results with regards to racial/ethnic disparities in chemotherapy use among breast cancer patients may be due to the different sample populations, treatment data sources, and treatment eligibility definitions used. This study examined chemotherapy disparity in the context of changing treatment guidelines and explored factors that may help explain treatment differences observed. The data come from a population-based study that included interview and medical record data (including state cancer registry) from non-Hispanic (nH) White, nH Black, and Hispanic breast cancer patients diagnosed in 2005–2008. Logistic regression using model-based standardization was used to estimate age-adjusted risk differences and multivariate analysis was conducted to identify explanatory factors of the differences. Per the 2005/2006 National Comprehensive Cancer Network (NCCN) guidelines, minority patients appeared more likely than nH White patients to receive a chemotherapy recommendation (0.87 vs 0.75, p = 0.003). When eligibility was determined per the 2007 guidelines, there was no disparity because under these guidelines, nH White patients were more likely than minority patients to have tumors that no longer required chemotherapy. There was evidence that chemotherapy advances for breast cancer patients are implemented in the clinical setting well ahead of NCCN guidelines. Finally, among eligible patients, chemotherapy recommendation was very high and virtually always accepted and received, with no disparities found at these points of clinical care. The findings suggest that an evaluation of guideline-adherent chemotherapy treatment patterns must carefully consider the definition of treatment eligibility, given ongoing changes in treatment guidelines and early uptake of new diagnostic tools and treatments.