Do Breast Cancer Survivors Have a Greater Risk of Type 2 Diabetes?

Breast cancer survivors have an increased risk of type 2 diabetes (T2D), according to a study being presented at ESMO Breast Cancer 2024, taking place May 15-17 in Berlin, Germany.

“Contemporary data on the risk of T2D after breast cancer are needed to guide preventive management, especially according to the type of adjuvant cancer therapy,” the researchers noted.

They used Danish medical registries to establish a nationwide population-based cohort of 74,526 breast cancer survivors and 372,630 matched comparisons. All subjects were 30 years of age and older. Patients in the population of interest were followed until a diagnosis of T2D, emigration, death, or December 31, 2022, whichever occurred first.

Breast Cancer Therapy Linked to T2D?

The results showed that adjuvant endocrine therapy (adjusted hazard ratio [aHR], 1.14; 95% CI, 1.10-1.19), particularly aromatase inhibitor treatment (aHR, 1.25; 95%CI, 1.18-1.32) and, to a lesser extent, tamoxifen (aHR, 1.05; 95% CI, 0.99-1.11) were correlated with a higher risk of T2D in women with breast cancer compared with matched breast cancer-free women. Notably, breast cancer survivors who did not receive endocrine therapy did not have an increased risk of T2D compared with matched breast cancer-free women. In the breast cancer cohort, the researchers observed that any chemotherapy (aHR, 1.10; 95%CI, 1.03-1.17) and radiation therapy (right-sided aHR, 1.18; 95%CI, 1.09-1.27 and left-sided aHR, 1.24; 95% CI, 1.15-1.33) were also associated with increased risk of T2D.

“Breast cancer survivors had a modestly increased risk of T2D compared with women without breast cancer. The excess T2D risk seems to be largely driven by breast cancer therapy modalities,” the researchers concluded.