In an Israeli case-cohort study reported in the Journal of Clinical Oncology, Hamood et al found that hormone therapy in breast cancer survivors was associated with an increased risk of developing diabetes.
The study involved a cohort of 2,246 women from the Leumit health-care fund diagnosed with primary nonmetastatic invasive breast cancer between 2002 and 2012 who survived ≥ 1 year after diagnosis and had no diagnosis of diabetes before or during the first year after diagnosis.
Among the cohort, 324 patients developed diabetes over a mean follow-up of 5.9 years. In multivariate analysis, receipt of any hormone therapy was associated with an increased risk of diabetes vs no use (hazard ratio [HR] = 2.40, P = .008), with risk being lower with tamoxifen use (HR = 2.25, P = .013) than with the use of aromatase inhibitors (HR = 4.27, P = .010).
Increased risk was observed for the use of hormone therapy for > 1 year (HR = 2.36, P = .009). Increased risk was also observed for use ≤ 1 year (HR = 6.48, P = .004), although the number of cases of diabetes occurring within 1 year of hormone therapy use was small.
The investigators concluded, “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.”
The study was supported in part by grants from the Council for Higher Education in collaboration with the Graduate Studies Authority at the University of Haifa.
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