Metformin Use and Risk of Non-Melanoma Skin Cancer: A Propensity-Matched Case-Control Study.

Background: There is literature that suggests metformin may play a protective role against the development of non-melanoma skin cancers. Given the significant burden of disease non-melanoma skin cancers represent, the possibility of a widely available and generally well-tolerated medication such as metformin as part of the prevention and treatment ladder warrants further research.

Objective: This study aims to evaluate the potential of metformin in reducing the risk of non-melanoma skin cancers, specifically squamous cell carcinoma and basal cell carcinoma, using the All of Us research database.

Methods: A retrospective case-control analysis was conducted using the All of Us database. Propensity score matching and multivariable regression analyses were performed to evaluate the impact of metformin on the incidence of squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) while controlling for confounding variables.

Results: Our results indicate a reduced risk of non-melanoma skin cancer following exposure to metformin in individuals diagnosed with both SCC and BCC. Subgroup analyses revealed that metformin exposure was associated with a decreased risk of BCC across all sex and ethnicity groups. Metformin use was also associated with a significantly lower risk of SCC, with univariable and multivariable ORs consistently showing reduced odds. However, metformin exposure was not significantly associated with decreased SCC risk in African American patients.

Conclusion: Our study's findings indicate a potential protective effect of metformin against skin cancer, particularly in patients with skin of color. Further prospective research is necessary to substantiate metformin's role in skin cancer chemoprevention within these populations.J Drugs Dermatol. 2024;23(12):1089-1095. doi:10.36849/JDD.8249.