In American men, prostate cancer is the most common type of cancer with the exception of skin cancer. It is also one of the deadliest forms of cancer in men, ranking after lung cancer in deaths and usually with a similar number of deaths as colorectal cancers. However, most prostate cancer patients survive the disease and die of unrelated causes. Earlier detection and better treatment have increased the survival rate over recent years.

The prostate is a walnut-size gland that is part of the male reproductive system. The prostate helps produce and distribute seminal fluid, which protects sperm cells in semen. The prostate is located in front of the rectum and below the  bladder. It surrounds the  upper part of the urethra, the tube that carries urine and semen out of the body through the penis. As men age, the prostate tends to enlarge and restrict the urethra, reducing the flow of urine.

The prostate gland initially develops in the male fetus and continues to grow as the male reaches adulthood. It attains its normal size and function when increased amounts of male hormones are produced at puberty.

The prostate is a gland and nearly all prostate cancers are adenocarcinomas, meaning they begin in the glandular cells. Prostate cancer usually grows slowly. In many cases, particularly in elderly men, the disease does not require treatment, and some men are never even aware they have the disease. This is also more common in elderly men. Sometimes, however, prostate cancer grows quickly. It can spread to the hip, spine and other nearby bones and lymph nodes. It is sometimes difficult for physicians to tell which prostate cancers are dangerous and which do not pose a threat. Less than 5 percent of prostate cancers are of types other than adenocarcinomas. These other types include small cell carcinomas, squamous cell carcinomas, transitional cell carcinomas and prostate sarcomas. Cancers of these types in the prostate may not respond to treatment and usually have a poorer prognosis.

The American Cancer Society (ACS) estimates that in 2007 there will be nearly 219,000 new cases of prostate cancer in the United States. The disease accounts for 10 percent, or about 27,000 of male cancer deaths a year. About one man in six will be diagnosed with prostate cancer, but only 1 man in 34 will die of the disease. According to the ACS:

• 99 percent of men diagnosed with prostate cancer survive it at least five years
• 93 percent survive it at least 10 years
• 77 percent survive it at least 15 years

The risk of prostate cancer increases with age, especially after 50. More than 65 percent of prostate cancer is diagnosed in men over age 65, according to the Centers for Disease Control and Prevention (CDC). The median age at diagnosis is 72.

Race and nationality are also variables. African Americans have a 60 percent higher risk than white and Hispanic Americans of developing prostate cancer, and their prognosis is not as good.  Asian Americans and Pacific Islanders are at lower risk. Prostate cancer is more common in North America and northwestern Europe than in other regions of the world. Scientists do not know why the disease is more likely to affect black Americans than white Americans but less likely to affect men in Asia, Africa and South America.

Despite its high survival rate, prostate cancer presents ongoing lifestyle considerations for some patients. Any treatment of prostate cancer may affect the male genital and urinary systems. It may present complications that affect a man's ability to control his bladder, in addition to sexual functioning.