Metformin may protect against esophageal squamous cell carcinoma

Metformin users appear to have a reduced risk of esophageal squamous cell carcinoma (ESCC) compared with nonusers, as shown in a population-based study.

Researchers looked at 13,050 patients newly diagnosed with ESCC (median age at diagnosis 70 years, 61.5 percent male) between 1994 and 2023 from all five Nordic countries (ie, Denmark, Finland, Iceland, Norway, and Sweden). These patients were matched to 130,500 randomly selected individuals without ESCC (control) from the general population based on age, sex, calendar year, and country.

Conditional logistic regression was performed to examine the association between metformin use and the development of ESCC. The models were adjusted for covariates including tobacco smoking, alcohol overconsumption, use of NSAIDs or aspirin, and use of statins. A dose-response analysis was also conducted in a subset of individuals with at least 5 years of observation time, based on the defined daily dose during the 5-year period.

A total of 725 patients in the ESCC group (5.6 percent) and 10,448 participants in the control group (8 percent) used metformin. Compared with nonuse, metformin use reduced the odds of ESCC by 36 percent (odds ratio [OR], 0.64, 95 percent confidence interval [CI], 0.59–0.69).

The odds were even lower for those exposed to a higher dosage of metformin (>1,278 defined daily dose in 5 years: OR, 0.52, 95 percent CI, 0.44–0.61).

These findings highlight the potential of metformin as a preventive option in high-risk individuals and as a potential future therapeutic agent for ESCC.