Researchers from Brown University in the United States examined metformin, a long-standing diabetes medicine that lowers blood sugar, and found early signals that it may reduce the risk of malignant skin tumors. The results appeared in a dermatology journal and contribute to growing interest in repurposing familiar drugs for cancer prevention. The team conducted a thorough review of patient records and treatment histories to see whether metformin’s metabolic effects could translate into protective actions against skin cancer. The work adds to a broad conversation about how metabolic medicines can influence cancer risk and progression beyond their original purpose. While the findings are hopeful, they do not guarantee protection for every patient and should be interpreted with the study design and the populations studied in mind. The work was carried out by Brown University investigators and collaborators and is now part of medical literature guiding clinicians, policymakers, and patients in the United States and Canada.
The study included more than eight thousand people diagnosed with basal cell carcinoma, about four thousand one hundred with squamous cell carcinoma, and more than eight thousand healthy volunteers who served as a comparison group. The research spanned multiple clinical sites and drew participants from diverse backgrounds to reflect real-world populations.
For each cancer patient, researchers linked data with four healthy individuals matched for age, race, ethnicity, and sex. Among people of European descent, metformin users showed a significantly lower risk of developing malignant skin tumors than nonusers. The protective effect varied by tumor type and other demographic factors, but the pattern suggested a possible preventive action linked to the drug’s metabolic actions.
Conversely, among Black patients with squamous cell carcinoma the drug did not seem protective. Investigators offer explanations, including cancers that often occur in skin areas with less sun exposure where metabolic interventions may have less influence, and the possible impact of chronic scarring and ongoing inflammation that could blunt metformin’s effects. These results remind clinicians that drug responses can differ across groups and underscore the need for more inclusive research.
Experts outline several mechanisms by which metformin could provide protection. The medication may disrupt energy pathways that cancer cells rely on, slow growth and progression. It might promote the death of abnormal cells, strengthen the immune system’s ability to detect cancer cells, reduce inflammation, and hinder the growth of new blood vessels that feed skin tumors. Taken together, these actions could contribute to a lower incidence of skin cancer in people taking metformin under appropriate circumstances.
Researchers emphasize that additional studies are needed to determine whether metformin could become a chemopreventive option for skin cancer. Randomized trials would be essential to establish causality, determine optimal dosing, identify who might benefit most, and assess long-term safety for preventive use. The findings feed into the growing interest in repurposing medicines for cancer prevention, a strategy that looks for new cancer prevention uses for existing drugs and may speed up future prevention options for high-risk groups.
Historically, metformin has been a cornerstone therapy for diabetes and related cardiovascular disease. The new results broaden the discussion about additional applications for the drug and how metabolic interventions may influence cancer risk. While not a practice-changing finding on its own, the study provides a foundation for further inquiry and underlines the importance of staying current with emerging evidence when considering preventive strategies for skin cancer.