Metformin for Prostate Cancer (PREMIUM Trial)

In current clinical practice, an acceptable standard treatment for locally advanced prostate cancer is radiation therapy in combination with hormone therapy (called Treatment B or Group B in this study). However, despite our best treatments, there is a risk that the prostate cancer may eventually return. As well, the hormonal therapy that is given to treat the prostate cancer is known to cause some harmful effects, with some patients using the hormones gaining weight, developing diabetes, having increased cholesterol levels, having increased blood pressure, and/or heart problems. This study is looking at whether Metformin, a drug that is commonly used to treat diabetes, can prevent patients from developing some of the harmful effects of the hormonal therapy. In treating diabetes, Metformin is known to decrease patients' sugar levels and also prevents patients from gaining weight, decreases their cholesterol levels, decreases the number of heart problems and allows patients to live longer. As a result, the researchers in this study are hopeful that Metformin will also be beneficial for men with prostate cancer on hormonal therapy by preventing them from developing these problems.