Prostate cancer is the sixth most common cancer in the world (in the number of new cases), the third most common cancer in men, and the most common cancer in men in Europe, North America, and some parts of Africa. Different geographical regions have varying incidence and mortality. The risk of prostate cancer is increased by African-American ethnicity, increasing age, positive family history, and other factors such as diet. Nonetheless, the causes of prostate cancer are not well understood compared with other common cancers like lung and breast cancer. The introduction of prostate-specific antigen (PSA) screening made an enormous impact on the incidence of prostate cancer, which increased in the early 1990s and is currently down to pre-PSA screening levels. Screening has caused a change in pattern of disease to an earlier stage but not lower grade. Yet we know little about what causes this disease, in the past 10 years interest in and funding for prostate cancer research have increased and several promising risk modifiers have been identified-eg, genetic predisposition, insulin growth factor (IGF) concentrations, and lycopene consumption.