HealthDay News — Breast cancer-specific mortality remains higher among women with diabetes who have longer diabetes duration or preexisting cardiovascular disease, according to a study published online in Diabetes Care.
Iliana C. Lega, MD, from the University of Toronto, and colleagues used Ontario administrative databases to compare the rate of receipt of breast cancer treatments between women with and without diabetes.
The researchers found that women with diabetes and stage III breast cancer were slightly less likely to receive chemotherapy (relative risk [RR], 0.93; 95% CI, 0.89 to 0.97), although this difference was not significant when adjusting for comorbidities (adjusted hazard ratio [aHR], 1.03; 95% CI, 0.93 to 1.13).
Similar results were seen for receipt of guideline-adherent radiotherapy (RR, 0.97; 95% CI, 0.95 to 0.99; aHR, 0.98; 95% CI, 0.94 to 1.02). After adjusting for comorbidities, all-cause mortality was higher in women with diabetes (aHR, 1.16; 95% CI, 1.06 to 1.27), but, overall, there was no increase in breast cancer-specific mortality.
However, among women with a longer duration of diabetes or preexisting cardiovascular disease there was increased all-cause and cancer-specific mortality.
“Although cancer treatments received were similar between women with and without diabetes, breast cancer-specific mortality remains higher among women with diabetes who have longer diabetes duration or preexisting cardiovascular disease,” the authors write. “This study uncovers new information about key risk factors for poorer prognosis in women with diabetes and breast cancer.”
Lega IC, Austin PC, Fischer HD, et al. The impact of diabetes on breast cancer treatments and outcomes: a population-based study [published online January 19, 2018]. Diabetes Care. doi: 10.2337/dc17-2012