The Prevention and Control of Cancer by Metformin in Patients with Type 2 Diabetes: A Systematic Mapping Review

ABSTRACT Objective Metformin is commonly used as a first line therapy for type 2 diabetes; however, existing evidence suggests an influence in oncology. The objective of this systematic mapping review was to describe current literature regarding metformin and its role in preventing and /or controlling cancer in patients with type 2 diabetes. Method We searched PubMed, Cochrane Library, and ClinicalTrials.gov in February 2018 and April 2019 to identify research studies, systematic reviews and meta-analyses. Of the 318 citations identified, 156 publications were included in this analysis. Results The most common cancer types researched were colorectal, liver, prostate, lung and breast with the United States contributing the most to this data. Author teams averaged six members and most studies were funded. Only 68% of the articles were available open access. Ovarian and esophageal cancers were amongst the least studied, but the most costly for care.