Does metformin usage improve survival in head and neck squamous cell carcinoma? A population-based study

BACKGROUND: We sought to expand upon preliminary data suggesting that metformin confers a survival benefit to patients with head and neck squamous cell carcinoma (HNSCC). METHODS: A large-scale retrospective cohort study of all patients in Ontario diagnosed with squamous cancer of the larynx, hypopharynx, and nasopharynx between Dec 1st 2007 to Dec 1st 2012 was undertaken. The Institute for Clinical and Evaluative Sciences was accessed to obtain patient demographic, treatment and outcome information. We included patients on metformin at the time of diagnosis. Kaplan Meier methods and Cox Regression models were used. RESULTS: Patients taking metformin at the time of diagnosis had a higher comorbid status but were otherwise similar to patients without metformin usage. Using multivariate analysis, neither overall survival nor disease specific survival was improved in patients on metformin (OS: HR 1.123, p = .338; DSS: HR 1.048, p = .792). CONCLUSIONS: No survival advantage was observed in patients with HNSCC taking metformin at the time of diagnosis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s40463-018-0322-7) contains supplementary material, which is available to authorized users.