Prostate cancer in young men: An emerging young adult and older adolescent challenge.

Prostate cancer in older adolescent and young adult men has increased in most countries. There is some evidence that this may be caused in part by underdiagnosis, prostate-specific antigen screening, and overdiagnosis. It also may be caused by trends in obesity, physical inactivity, HPV infection, substance exposure, environmental carcinogens, and/or referral patterns. How the biology of these cancers differs from that in older men and how the etiologies vary from country to country remain to be determined.