Analysis of the Effect of Metformin in the Treatment of Oral and Oropharyngeal Cancer

Abstract

Objectives: Patients with diabetes mellitus (DM) are at significantly higher risk for many forms of cancers. There have been studies about the effect of metformin in cancer, but few studies presented in head and neck cancer. In this study, we investigated the anti-cancer effect of metformin in oral and oropharyngeal cancer. Methods: Patients with type II DM who were diagnosed with oral and oropharyngeal cancers and treated in our institution from 2004 through 2010 were enrolled. Medical records, imaging, and pathologic reports were reviewed retrospectively. Results: Of 2286 patients who were diagnosed with head and neck cancers in that period, 8.6% of patients had type II DM, and eventually 68 patients were enrolled. Half of them had history of using metformin, and mean age was 69.3 years. Metformin usage did not affect overall survival ( P = .359) and recurrence ( P = .538) in oral and oropharyngeal cancer patients. The same results were shown when patients limited in squamous cell carcinoma and early stage cancer. Conclusions: Metformin usage was not associated with favorable survival or recurrence outcomes in oral and oropharyngeal cancer patients. Subset analysis revealed possible association of metformin usage with pathology/stage. A large prospective cohort study is warranted to elucidate the effect of metformin usage on oral and oropharyngeal cancer.