Abstract A50: Is there a reverse racial/ethnic disparity in chemotherapy treatment among breast cancer patients?
Authors: Silva Abigail , Rauscher Garth H. , Hoskins Kent , Rao Ruta D. 
Published: August 2014

Background: There is evidence that minority women are more likely than White women to receive suboptimal breast cancer care, however this may not be the case with regards to chemotherapy for which White women may be less likely than Black or Hispanic women to receive chemotherapy. In order to better understand this apparent reverse disparity, this study seeks to examine how changes in the treatment guidelines may affect the disparity observed in chemotherapy treatment.

Methods: Interview and medical record data came from a population-based study of 989 breast cancer patients (397 non-Hispanic White, 411 non-Hispanic Black, 181 Hispanic) diagnosed between 2005-2008. Of these, 87% (N=849) consented to medical record abstraction, including a linkage with the Illinois State Cancer Registry (ISCR). Patients who consented to the medical record abstraction and had single primary tumors were considered for this study. Eligibility for chemotherapy (CT) was defined according to the National Comprehensive Cancer Network (NCCN) guidelines in two ways. First, CT eligibility was defined according to the 2005 guidelines and then also according to the 2006-2007 guidelines. The outcome variables included treatment recommendation, acceptance, and initiation which were derived from the interview, medical record, and ISCR data. Age-adjusted risk differences (RDs) were estimated using logistic regression (with marginal standardization) in order to report percentages.

Results: The medical record consent rate was 87%. Among those with a medical record consent and single primary tumors (n=824), 460 were CT-eligible per the 2005 NCCN guidelines and 284 were CT-eligible per the 2006-2007 guidelines (eligibility could not be determined for 107 node-negative, hormone receptor-positive women because their HER2 status was unavailable). Using the 2005 NCCN guidelines, chemotherapy was recommended to 74% of CT-eligible patients and non-Hispanic White patients were less likely than minority patients to receive a recommendation (0.62 vs. 0.75, RD=13%p=0.001). However, if the 2006-2007 guidelines were used, 94% of eligible patients received a recommendation and there were no racial/ethnic differences. Of these women who received a recommendation, 98% accepted it and a resulting 100% initiated treatment. However, the overall treatment initiation was 92% and in multivariate analysis, patients with lower income (p=0.03), breast conserving surgery (p=0.01), and low grade tumors (p=0.05) were less likely to initiate chemotherapy.

Conclusions: The apparent reverse racial/ethnic disparity in chemotherapy treatment may appear or disappear depending on which guideline is used to determine treatment eligibility. It is reasonable that clinicians change treatment practices ahead of published guidelines as to provide their patients with the best care. Future studies on treatment quality should consider this when defining treatment eligibility. The vast majority of CT-eligible patients are receiving chemotherapy, although patients with less aggressive appearing tumors are less likely to receive CT.

Citation Format: Abigail Silva, Garth H. Rauscher, Kent Hoskins, Ruta D. Rao. Is there a reverse racial/ethnic disparity in chemotherapy treatment among breast cancer patients? [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr A50.