Who’s who in prostate cancer? A medical market research guide November 2, 2013 What is prostate cancer? Prostate cancer is a type of cancer that occurs when the cells in the prostate gland grow out of control. It usually develops very slowly and it may be some years before symptoms start to appear when the prostate is large enough to affect the urethra. The causes of prostate cancer are largely unknown; however we do know that the risk of developing this type of cancer is higher in men over the age of 50 and that men with first degree relatives who have had prostate cancer also have an increased risk. Back to blogs written by GKA