Hormone therapy appeared associated with an increased risk for diabetes among women who survived breast cancer, according to researchers in Israel.
However, the survival benefits of hormone therapy outweighed the possible risks, according to researchers.
“Breast cancer has become an increasingly survivable disease probably because of the continued improvements in detection interventions and advancements in treatment,” Hatem Hamood, MD, of Leumit Health Services in Karmiel, Israel, and colleagues wrote. “However, many survive only to be faced with another debilitating illness that is absent or subclinical at the end of therapy. One such sequel is diabetes. ... Previous studies have suggested diabetes as an independent risk factor for the development of breast cancer, but few have investigated the inverse direction: breast cancer induction of diabetes.”
The researchers conducted a case-cohort study of 2,246 women who survived breast cancer. All were diagnosed with nonmetastatic disease from 2002 through 2012.
Hamood and colleagues sampled a random 20% of patients at baseline to identify cases of diabetes.
During a mean follow-up of 5.9 years, 324 patients developed diabetes.
The cumulative crude incidence of diabetes was 20.9% (95% CI, 18.3-23.7), accounting for death as a competing risk.
Hormone therapy increased risk for diabetes in adjusted models (HR = 2.4; 95% CI, 1.6-4.55).
Use of tamoxifen presented less of a risk for diabetes (HR = 2.25; 95% CI, 1.19-4.26) than use of aromatase inhibitors (HR = 4.27; 95% CI, 1.42-12.84).
“Hormone therapy is a significant risk factor of diabetes among breast cancer survivors,” the researchers wrote. “The underlying mechanism is unclear, and additional research is warranted. Although cessation of treatment is not recommended and progression of breast cancer often is inevitable, devised strategies aimed at lifestyle modications in patients at high risk [for] diabetes could at least preserve the natural history of breast cancer.” – by Andy Polhamus
Disclosures: The authors report no relevant financial disclosures.