National Cancer Institute. Between 1950 and 1997, the age-adjusted rate of new cases of prostate cancer more than doubled, probably owing to more widespread screening for the disease. The rate has recently begun to decline. The reasons for the decline through the 1990s are unclear. Such factors as more effective treatments and screening methods offer a possible explanation.
Research is ongoing to help explain the changing rates in recent years.
Prostate cancer is still the second-leading cause of cancer deaths in men, behind lung cancer. Age is the most important and best-studied risk factor for prostate cancer. The disease is extremely rare in men under age 40, but risk increases greatly with age. More than 75 percent of cases are diagnosed in men over age 65. Race is another major risk factor.