Common drugs for type 2 diabetes and obesity do not increase breast cancer risk

WASHINGTON—Commonly used medications for type 2 diabetes and obesity called glucagon like peptide-1 receptor agonists (GLP-1 RAs), are not associated with an increased risk of breast cancer, despite previous studies that suggested a possible link, according to a study presented virtually at ENDO 2021, the Endocrine Society’s annual meeting.

“GLP-1RAs can be used as adjunct to diet and exercise in subjects with type 2 diabetes and those without type 2 diabetes and excess weight, without an increased risk of breast cancer or noncancerous masses in the breast,” said lead researcher Giovana Fagundes Piccoli, M.D., of the Universidade Federal do Rio Grande do Sul in Brazil.

GLP-1 RAs have been shown to be effective in treating obesity and type 2 diabetes and in reducing heart disease. These drugs include albiglutide (Tanzeum); dulaglutide (Trulicity); exenatide (Byetta); extended-release exenatide (Bydureon); liraglutide (Victoza, Saxenda); lixisenatide (Adlyxin); and semaglutide (Ozempic, Rybelsus). In clinical trials of liraglutide, subjects treated with the active drug instead of a placebo had a higher number of breast cancers. The new study was designed to assess whether patients treated with GLP-1 RAs had a higher risk of breast cancer or benign growths in the breasts called neoplasms.

Piccoli reviewed 52 randomized controlled trials that compared GLP-1 RAs with non-GLP-1 RAs (either other diabetes or weight-loss drugs or placebos) in adults with overweight, obesity, prediabetes or diabetes. The studies had a minimum follow-up period of 24 weeks and reported at least one event of breast cancer or benign breast neoplasm. They included a total of 90,360 participants.

The analysis found treatment with GLP-1 RAs was not associated with increased rates of breast cancer or benign or premalignant breast neoplasms, compared to placebo or other diabetes or weight-loss drugs. Among 48,267 subjects treated with GLP-1 RAs, 130 developed breast cancer, compared to 107 of 40,755 controls.

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