Glucagon-like peptide-1 (GLP-1) analogs are incretin-based drugs used as the second or third-line treatments for type-2 diabetes. Some recent studies have indicated that these drugs could be associated with a potential risk of breast cancer. This study aims to investigate the risk of breast cancer associated with the intake of GLP-1 in women with type-2 diabetes.

This population-based cohort study included a total of 44,984 women aged 40 years or more who were newly treated with glucose-lowering drugs – GLP-1 analogs and DPP-4 inhibitors. The time-varying use of GLP-1 analogs and DPP-4 inhibitors was compared. The primary outcome of the study was time-dependent hazard ratios.

During a mean follow-up of 3.5 years, 549 incidents of breast cancer were reported. When compared with the use of DPP-4 inhibitors, the use of GLP-1 analogs was not associated with a higher risk of breast cancer (4.4 vs. 4.3 cases per 1,000 person-years). The hazard ratios for breast cancer increased with the longer duration of use of both DPP-1 inhibitors and GLP-1 analogs. The peak duration of use was two to three years.

The research concluded that the use of GLP-1 inhibitors was not associated with an increased risk of breast cancer in women with type-2 diabetes.