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Prostate cancer is cancer that starts in the 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.

Cancer - prostate

The cause of prostate cancer is unknown. Some studies have shown a relationship between high dietary fat intake and increased testosterone levels.

There is no known association with an enlarged prostate or 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 age 75. Prostate cancer is rarely found in men younger than 40.

People who are at higher risk include:

• African-American men
• Men who are older than 60
• Farmers
• Tire plant workers
• Painters
• Men who have been exposed to cadmium

The lowest number of cases occurs in Japanese men and those who do not eat meat (vegetarians).

Thanks to PSA testing, most prostate cancers are now found before they cause symptoms. Although most of the symptoms listed below can occur with prostate cancer, they are more likely to be associated with noncancerous 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

Other symptoms that may occur with this disease:

• Excessive urination at night
• Urinary leakage (incontinence)
• Bone pain or tenderness
• Blood in the urine (hematuria)
• Abdominal pain
• Low red blood cell count (anemia)
• Unintentional weight loss
• Lethargy

A rectal exam will often show an enlarged prostate with a hard, irregular surface.

A number of tests may be done to diagnose prostate cancer:

• PSA test (may be high, although noncancerous enlargement of the prostate can also increase PSA levels)
• Free PSA (may help tell the difference between BPH and prostate cancer)
• AMACR (a newer test that is more sensitive than the PSA test for determining prostate cancer)
• Urinalysis (may show blood in the urine)
• Urine or prostatic fluid testing (may reveal unusual cells)

Prostate biopsy is the only test that can confirm the diagnosis.

The following tests may be done to determine whether the cancer has spread:

• CT scan
• Bone scan
• Chest x-ray

Health care providers use a system called staging to describe how far the cancer has grown. Tumor size, and how far the cancer has spread outside of the prostate determine the stage. Identifying the correct stage may help the doctor recommend the best treatment.

There are several different ways to stage tumors, including:

• The TNM staging system (most common)
• The A-B-C-D staging system, also known as the Whitmore-Jewett system

The grade of a tumor describes how aggressive a cancer might be. The more tumor cells differ from normal tissue, the faster these cells are likely to grow. The grading system for prostate cancer is called the Gleason grade or score. Higher scores are usually faster growing cancers.

You can ease the stress of illness by joining a support group whose members share common experiences and problems. See: Support group - prostate cancer

The outcome varies greatly. This is mainly because the disease is found in older men, who may have a variety of other diseases or conditions such as heart or respiratory disease, or disabilities. The outcome is also affected by the stage and grade of the disease when you are diagnosed.

Impotence is a potential complication after prostate removal or radiation therapy. Recent improvements in surgical procedures have made this complication less common. Urinary incontinence is another possible complication. Medications can have side effects, including hot flashes and loss of sexual desire.

Call for an appointment with your health care provider if you are a man over age 40 who has:

• Never been screened for prostate cancer (by rectal exam and PSA level)
• Not had regular, annual exams
• A family history of prostate cancer

Discuss the advantages and disadvantages to PSA screening with your health care provider.

There is no known way to prevent prostate cancer. Following a vegetarian, low-fat diet or one that is similar to the traditional Japanese diet may lower your risk. Early identification (as opposed to prevention) is now possible by screening men over age 40 each year with a digital rectal examination (DRE) and PSA blood test.

There is a debate, however, as to whether PSA testing should be done in all men. There are several potential downsides to PSA testing. The first is that a high PSA level does not always mean that a patient has prostate cancer. The second is that health care providers are detecting and treating some very early-stage prostate cancers that may never have caused the patient any harm. The decision about whether to use a PSA testing to screen for prostate cancer should be based on a discussion between the patient and his health care provider.

Andriole GL, Crawford ED, Grubb RI 3rd, Buys SS, Chia D, Church TR, et al. Mortality results from a randomized prostate-cancer screening trial. N Engl J Med. 2009;360:1310-1319.

Babaian RJ, Donnelly B, Bahn D, Baust JG, Dineen M, Ellis D, et al. Best practice statement on cryosurgery for the treatment of localized prostate cancer. J Urol. 2008;180:1993-2004.

NCCN Clinical Practice Guidelines in Oncology: Prostate cancer. V.2.2009. Accessed June 2009.

Schröder FH, Hugosson J, Roobol MJ, Tammela TL, Ciatto S, Nelen V, et al. Screening and prostate-cancer mortality in a randomized European study. N Engl J Med. 2009;360:1320-1328.

Walsh PC, DeWeese TL, et al. Clinical practice: localized prostate cancer. N Engl J Med. 2007;357(26):2696-2705.

Wilt TJ, MacDonald R, et al. Systematic review: comparative effectiveness and harms of treatments for clinically localized prostate cancer. Ann Intern Med. 2008;148(6):435-448.