Metformin Not Effective in Treatment of Patients With Early Stage Breast Cancer

Metformin, a medication commonly used to treat patients with type 2 diabetes, does not improve invasive, disease-free survival of patients with breast cancer, according to findings in a recent study.

To determine whether adjuvant metformin use was effective in the treatment of patients with high-risk, operable breast cancer without diabetes, the researchers conducted a randomized, double-blind, placebo-controlled trial.

A total of 3469 (mean age, 52.4 years; 3643 women [99.8%]) patients were enrolled in the clinical study. The patients were randomly assigned to receive 850 mg of oral metformin twice per day (n = 1824) or a placebo twice per day (n = 1825) for 5 years.

Primary analysis was conducted for patients who were ER/PgR+ (n=2533) with a median duration of follow-up of 96.2 months (range, 0.2-121 months).

“Among patients with high-risk operable breast cancer without diabetes, the addition of metformin vs placebo to standard breast cancer treatment did not significantly improve invasive disease–free survival,” the researchers concluded.

—Jessica Ganga

Reference:

Goodwin PJ, Chen BE, Gelmon KA, et al. Effect of metformin vs placebo on invasive disease-free survival in patients with breast cancer. The MA.32 randomized clinical trial.  JAMA. 2022;327(20):1963-1973. doi:10.1001/jama.2022.6147