Prostate cancer is cancer that grows in prostate gland. The prostate is a small, walnut-sized structure that makes up part of a man's reproductive system. It wraps around the urethra, the tube that carries urine out of the body.

The cause of prostate cancer is unknown, although some studies have shown a relationship between high dietary fat intake and increased testosterone levels. When testosterone levels are lowered either by surgical removal of the testicles (castration, orchiectomy) or by medication, prostate cancer can slowly get better.

There is no known association with benign prostatic hyperplasia (BPH).

Prostate cancer is the third most common cause of death from cancer in men of all ages and is the most common cause of death from cancer in men over 75 years old. Prostate cancer is rarely found in men younger than 40.

Men at higher risk include African-America men older than 60, farmers, tire plant workers, painters, and men exposed to cadmium. The lowest number of cases occurs in Japanese men and those who do not eat meat (vegetarians).

Prostate cancers are grouped according to how quickly they spread and how different they are from the surrounding prostate tissue. This is called staging. There are several different ways to stage tumors, a common one being the A-B-C-D staging system, also known as the Whitmore-Jewett system:

• Stage A: Tumor is not felt on physical examination, and is usually detected by accident after prostate surgery is done for other reasons.
• Stage B: Tumor is only in the prostate and usually detected during a physical exam or with a blood test (PSA test).
• Stage C: Tumor has spread beyond the prostate but is not in the lymph nodes.
• Stage D: Tumor has spread (metastasized) to lymph nodes or other parts of the body, such as the bone and lungs.

This system also contains several substages.

With the advent of PSA testing, most prostate cancers are now found before they cause symptoms. Additionally, while most of the symptoms listed below can be associated with prostate cancer, they are more likely to be associated with non-cancerous conditions.

• Urinary hesitancy (delayed or slowed start of urinary stream)
• Urinary dribbling, especially immediately after urinating
• Urinary retention
• Pain with urination
• Pain with ejaculation
• Lower back pain
• Pain with bowel movement

Additional symptoms that may be associated with this disease:

• Excessive urination at night
• Incontinence
• Bone pain or tenderness
• Hematuria (blood in the urine)
• Abdominal pain
• Anemia
• Unintentional weight loss
• Lethargy

A rectal exam often reveals an enlarged prostate with a hard, irregular surface. A number of tests may be done to confirm the diagnosis of prostate cancer.

• PSA test may be high, although non-cancerous enlargement of the prostate can also increase PSA levels.
• Free PSA may help tell the difference between BPH and prostate cancer.
• Urinalysis may show blood in the urine.
• Urine or prostatic fluid cytology may reveal unusual cells.
• Prostate biopsy confirms the diagnosis.
• CT scans may be done to see if the cancer has spread.
• A bone scan may be done to see if the cancer has spread.
• Chest x-ray may be done to see if the cancer has spread.

A newer test called AMACR is more sensitive for determining the presence of prostate cancer than the PSA test.