Breast cancer survival, survival disparities, and guideline-based treatment

• Authors: Deirdre A. Hill, University of New Mexico; Sarah Friend, Emory University; Lesley Lomo, University of New Mexico; Charles Wiggins, University of New Mexico; Marc Barry, University of New Mexico; Eric Prossnitz, University of New Mexico; Melanie Royce, University of New Mexico
• Journal Title: Breast Cancer Research and Treatment
• Volume: Volume 170, Number 2
• Publisher: Springer (part of Springer Nature): Springer Open Choice Hybrid Journals | 2018-07, Pages 405-414
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1007/s10549-018-4761-7
• Subjects: Health Sciences, Oncology; Health Sciences, Medicine and Surgery

Abstract

Purpose: The role of appropriate therapy in breast cancer survival and survival disparities by race/ethnicity have not been fully elucidated. We investigated whether guideline-inconsistent therapy contributed to survival differences overall and among Hispanics relative to non-Hispanic white (NHW) women in a case-cohort study. Methods: This study included a 15% random sample of female invasive breast cancer patients diagnosed from 1997–2009 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-consistent treatment was assessed among white women aged < 70 who were free of contraindications for recommended therapy, had stage I–III tumors, and had survived at least 12 months. Hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer death were estimated using Cox proportional hazards models. Results: The median survival was 101 months. The included women represented 4635 patients and 449 breast cancer deaths. Women who met specific NCCN treatment criteria but 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) had an increased risk of breast cancer death relative to those who did receive these therapies. Guideline-consistent therapy receipt did not differ between Hispanic and NHW women for chemotherapy (84.2% vs. 81.3%, respectively), radiotherapy (89.2% vs. 91.1%, respectively) or endocrine therapy (89.2% vs. 85.8%, respectively), and it did not influence Hispanic survival disparities. Conclusions: Guideline-concordant receipt of radiotherapy and 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.