The prostate gland—a walnut-sized gland located below the bladder and in front of the rectum—makes and secretes seminal fluid, which is released to form part of semen.
As in other organs in the body, cancerous (also called malignant) cells can develop in the prostate. These cancerous cells develop at different rates. They often develop so slowly that most men who have prostate cancer will never know they have it and will actually die of something else. About one man in six will get prostate cancer during his lifetime, but far fewer—only one man in 35 (about three percent)—will die of the disease.
It’s estimated that 15 to 30 percent of American men over 50—and 60 to 70 percent of men who reach age 80—have small, nonaggressive prostate cancers that haven’t spread and are not clinically significant.
But prostate tumors can metastasize and spread to other vital organs. Once the cancer has spread far beyond the prostate gland, there is no way to cure it. For a 50-year-old man, the lifetime risk of developing any type of prostate cancer is about 42 percent. In approximately 23 percent of the men with “latent” cancer, the disease will develop to a point where it is clinically significant; about one in three of these men will die of prostate cancer.
Cancer of the prostate is the most commonly diagnosed cancer (other than skin cancer) in men and the second leading cause of cancer deaths in men after lung cancer. The American Cancer Society estimates that 239,000 new cases of prostate cancer were diagnosed in 2013 and that about 30,000 men died of the disease.
Because of increasing use of the PSA test, which measures blood levels of prostate-specific antigen (a protein produced in the prostate that may be elevated when cancer is present), the reported incidence of prostate cancer began rising after 1994, when the PSA test was first approved as a screening tool. At about the same time, prostate cancer death rates began to decline.
Whether this trend has been due to earlier detection of prostate cancer through routine use of the PSA test is an issue of great debate. The incidence of prostate cancer has been relatively stable since 1998, presumably reflecting changing patterns in PSA testing. The mortality rate has been decreasing since the mid-1990s.
At present, there is no good way to prevent prostate cancer. Finasteride and dutasteride, drugs prescribed to reduce symptoms caused by an enlarged prostate, have been shown in trials to reduce the overall risk of low-grade prostate cancers, but they may raise the risk of the most serious form of the disease—which is why the Food and Drug Administration (FDA) has warned men not to use these drugs for cancer prevention. However, a 2013 study published in the New England Journal of Medicine found that finasteride did not increase mortality rates from prostate cancer. Men should discuss the pros and cons of these drugs with their doctors.