Purpose Breast cancer treatments have been associated with an increased risk of multiple health-related adverse outcomes, but the relationship with diabetes remains unclear. This study investigated the association between hormone therapy and diabetes risk in breast cancer survivors. Patients and Methods We performed a case-cohort study of 2,246 female survivors recruited from the Leumit health care fund who were diagnosed with primary nonmetastatic invasive breast cancer in 2002 through 2012. A 20% random subcohort was sampled at baseline, and all diabetes cases were identified. Adjusted hazard ratios (HRs) with 95% CIs were estimated by weighted Cox proportional hazards regression models. Results Of 2,246 breast cancer survivors, 324 developed diabetes over a mean follow-up of 5.9 years. The crude cumulative incidence of diabetes that accounted for death as a competing risk was 20.9% (95% CI, 18.3% to 23.7%). In multivariable-adjusted models, hormone therapy was associated with increased diabetes risk (HR, 2.40; 95% CI, 1.26 to 4.55; P = .008). The hazard for tamoxifen use (HR, 2.25; 95% CI, 1.19 to 4.26; P = .013) was less pronounced than the use of aromatase inhibitors (HR, 4.27, 95% CI, 1.42 to 12.84; P = .010). Conclusion Active hormone therapy is a significant risk factor of diabetes among breast cancer survivors. Although cessation of treatment is not recommended because the survival benefits of hormone therapy outweigh the risks, preventive strategies aimed at lifestyle modifications may minimize the risk.
Bibliographical noteFunding Information:
Supported in part by Grants No. 11658745 and 11658760 from the Council for Higher Education in collaboration with the Graduate Studies Authority at the University of Haifa. The results, conclusions, views, and opinions are those of the authors and are not to be construed as the official policy of Israel’s Ministry of Health or of LHS. We thank the advisory committee and all participating breast cancer survivors. We also thank Natan Kahan, PhD, for help and support with data acquisition and study approval.
Copyright © 2018 American Society of Clinical Oncology. All rights reserved.
ASJC Scopus subject areas
- Cancer Research