Metformin reduces risk of BCC development

Treatment with metformin, even at low doses, appears to lower the risk of basal cell carcinoma (BCC) development, results of a recent study have shown.

“Metformin has anticarcinogenic properties and is also known to inhibit the sonic hedgehog pathway,” the authors said.

This population-based case-control study sought to describe the association between metformin use and invasive squamous cell carcinoma (SCC), SCC in situ, and BCC. The authors enrolled all 6,880 patients diagnosed with first-time BCC, SCC in situ, or invasive SCC in Iceland between 2003 and 2017, as well as 69,620 controls. Conditional logistic regression was used to calculate multivariate odds ratios (ORs).

Use of metformin, even at low doses, displayed a significant association with a decreased risk of developing BCC (OR, 0.71, 95 percent confidence interval [CI], 0.61–0.83). No increased risk of developing SCC was noted. In addition, the risk of SCC in situ was slightly increased in the 501–1,500 daily dose unit category (OR, 1.40, 95 percent CI, 1.00–1.96).

A recent study showed that metformin could be used as an adjuvant treatment to photodynamic therapy (PDT) in BCC. Specifically, it increased the response to methyl-aminolevulinate-PDT in murine BCC cells resistant to PDT with aerobic glycolysis. [Cancers (Basel) 2020;12:668]

“Metformin might have potential as a chemoprotective agent for patients at high risk of BCC, although this will need confirmation in future studies,” the authors said.

The current study had certain limitations. Its retrospective nature had no capacity to adjust for ultraviolet exposure, Fitzpatrick skin type, and comorbidities.