Abstract
PURPOSE: The role of appropriate therapy in breast cancer survival and survival disparities by race/ethnicity has not been fully elucidated. We investigated whether lack of guideline-recommended therapy contributed to survival differences overall and among Hispanics relative to non-Hispanic white (NHW) women in a case-cohort study. METHODS: The study included a 15% random sample of female invasive breast cancer patients diagnosed from 1997 to 2009 in 6 New Mexico counties and all deaths due to breast cancer-related causes. Information was obtained from comprehensive medical chart reviews. National Comprehensive Cancer Network (NCCN®) guideline-recommended treatment was assessed among white women aged < 70 who were free of contraindications for recommended therapy, had stage I-III tumors, and survived ≥ 12 months. Hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer death were estimated using Cox proportional hazards models. RESULTS: Included women represented 4635 patients and 449 breast cancer deaths. Women who did not receive radiotherapy (HR 2.3; 95% CI 1.2-4.4) or endocrine therapy (HR 2.0; 95% CI 1.0-4.0) as recommended by guidelines had an increased risk of breast cancer death, relative to those treated appropriately. Receipt of guideline-recommended therapy did not differ between Hispanic and NHW women for chemotherapy (84.2% vs. 81.3%, respectively), radiotherapy (89.2% vs. 91.1%), or endocrine therapy (89.2% vs. 85.8%), thus did not influence Hispanic survival disparities. CONCLUSIONS: Lack of guideline-recommended radiotherapy or endocrine therapy contributed to survival as strongly as other established prognostic indicators. Hispanic survival disparities in this population do not appear to be attributable to treatment differences.