Prostate cancer is the second most common type of cancer among men in this country. Only skin cancer is more common. Out of every three men who are diagnosed with cancer each year, one is diagnosed with prostate cancer.

Cancer that forms in tissues of the prostate (a gland in the male reproductive system found below the bladder and in front of the rectum). Prostate cancer usually occurs in older men.

The prostate is part of a man's reproductive system. It is located in front of the rectum and under the bladder. It surrounds the urethra, the tube through which urine flows. A healthy prostate is about the size of a walnut.

The prostate makes part of seminal fluid. During ejaculation, seminal fluid helps carry sperm out of the man's body as part of semen.

Male hormones (androgens) make the prostate grow. The testicles are the main source of male hormones, including testosterone. The adrenal gland also makes testosterone, but in small amounts.

If the prostate grows too large, it squeezes the urethra. This may slow or stop the flow of urine from the bladder to the penis.

Cancer in the Prostate

When prostate cancer spreads, cancer is often found in nearby lymph nodes. If cancer has reached these nodes, it also may have spread to other lymph nodes, the bones, or other organs.

When cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if prostate cancer spreads to bones, the cancer cells in the bones are actually prostate cancer cells. The disease is metastatic prostate cancer, not bone cancer. For that reason, it is treated as prostate cancer, not bone cancer. Doctors call the new tumor "distant" or metastatic disease.

Risk Factors

No one knows the exact causes of prostate cancer. Doctors often cannot explain why one man develops prostate cancer and another does not. However, we do know that prostate cancer is not contagious. You cannot "catch" it from another person.

Research has shown that men with certain risk factors are more likely than others to develop prostate cancer. A risk factor is something that may increase the chance of developing a disease.

Studies have found the following risk factors for prostate cancer:

• Age: Age is the main risk factor for prostate cancer. This disease is rare in men younger than 45. The chance of getting it goes up sharply as a man gets older. In the United States, most men with prostate cancer are older than 65.
• Family history: A man's risk is higher if his father or brother had prostate cancer.
• Race: Prostate cancer is more common in African American men than in white men, including Hispanic white men. It is less common in Asian and American Indian men.
• Certain prostate changes: Men with cells called high-grade prostatic intraepithelial neoplasia (PIN) may be at increased risk for prostate cancer. These prostate cells look abnormal under a microscope.
• Diet: Some studies suggest that men who eat a diet high in animal fat or meat may be at increased risk for prostate cancer. Men who eat a diet rich in fruits and vegetables may have a lower risk.