Metformin for the chemoprophylaxis of cancer: an update systematic review about the role of metformin in cancer prevention.

Abstract

Objective: Metformin has been evaluated as a possible molecule capable of preventing cancer. We performed a systematic review on this topic in 2014. However, since then, a plethora of studies has been conducted. Therefore we decided to undertake an updated systematic review. Methods: Systematic search in Medline from March 1st 2014 to May 16 2017, using the medical subject headings (MeSH descriptors) neoplasms, cancer and metformin, limiting the search to humans. Two independent investigators collected information. Results: 1428 potentially eligible articles were identified and 74 were eligible. Most studies showed conflicting results, with the majority being retrospective. However, a randomized placebo-controlled trial demonstrated that metformin reduced the incidence of colorectal polyps and adenomas. Conclusion: Except for colorectal cancer secondary prevention, current evidence does not support the use of metformin as a chemoprophylaxis agent in solid tumors. Controlled trials are necessary to prove the role of metformin on cancer prevention.

Keywords

• Metformin
• Chemoprevention
• Review
• Metformina
• Quimioprevenção
• Revisão