Overview

Cancer begins when normal cells in the prostate begin to change and grow uncontrollably, forming a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body).

Prostate cancer is a malignant tumor that begins in the prostate gland of men. The prostate is a walnut-sized gland located behind the base of the penis, in front of the rectum, and below the bladder. It surrounds the urethra, the tube-like channel that carries urine and semen through the penis. The prostate's main function is to produce seminal fluid, the liquid in semen that protects, supports, and helps transport sperm.

Some prostate cancers grow very slowly and may not cause symptoms or problems for years. In this situation, the cause of death is usually not from prostate cancer, but other causes. However, if cancer does metastasize (spread) to other parts of the body, it can cause pain, fatigue, and other symptoms. Prostate cancer is somewhat unusual from other types of cancer, in that many tumors that are diagnosed do not spread from the prostate. And often, even metastatic prostate cancer can be successfully treated, with the person surviving in good health for some years.

More than 95% of prostate cancers are adenocarcinomas, cancer that develops in glandular tissue. A rare type of prostate cancer known as neuroendocrine cancer or small cell anaplastic cancer tends to spread earlier, but usually does not produce prostate-specific antigen (PSA), a tumor marker discussed later in this section. Read more about neuroendocrine tumors.

Statistics

Prostate cancer is the most common cancer among men. In 2009, an estimated 192,280 men in the United States will be diagnosed with prostate cancer. It is estimated that 27,360 deaths from this disease will occur this year.

Prostate cancer is the second leading cause of cancer death in men. Although the number of deaths from prostate cancer is declining among all men, the death rate remains more than twice as high in black men than in white men.

More than 90% of all prostate cancer cases are discovered when the disease is limited to the prostate and surrounding organs. In these cases, nearly 100% of men are expected to live at least five years after diagnosis. The five-year relative survival rate (the percentage of people who survive after the cancer is detected, excluding those who die from other diseases) of men with prostate cancer is 99%. The 10-year and 15-year relative survival rates are 93% and 79%, respectively.

Cancer survival statistics should be interpreted with caution. These estimates are based on data from thousands of cases of this type of cancer in the United States each year, but the actual risk for a particular individual may differ. It is not possible to tell a man how long he will live with prostate cancer. Because survival statistics are often measured in multi-year intervals, they may not represent advances made in the treatment or diagnosis of this cancer.

Statistics adapted from the American Cancer Society's publication, Cancer Facts & Figures 2009.

Find out more about basic cancer terms used in this section.