Metformin is a biguanide oral hypoglycaemic agent commonly used for the treatment of type 2 diabetes mellitus. In addition to its anti-diabetic effect, metformin has also been associated with a reduced risk of cancer incidence of a number of solid tumours, including prostate cancer (PCa). | Metformin and longevity METAL A window of opportunity study investigating the biological effects of metformin in localised prostate cancer