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; Biopsy - prostate; Prostate biopsy; Gleason score
Causes, incidence, and risk factors
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, who are also likely to develop cancer at every age
- Men who are older than 60
- Men who have a father or brother with prostate cancer
Other people at risk include:
- Men exposed to agent orange exposure
- Men who abuse alcohol
- Men who eat a diet high in fact, especially animal fat
- Tire plant workers
- Men who have been exposed to cadmium
The lowest number of cases occurs in Japanese men living in Japan (this benefit is lost after one generation of living in the U.S.) and those who do not eat meat (vegetarians).
A common problem in almost all men as they grow older is an enlarged prostate (benign prostatic hyperplasia, or BPH). This problem does not raise your risk of prostate cancer.
The PSA blood test is often done to screen men for prostate cancer. Because of PSA testing, most prostate cancers are now found before they cause any symptoms.
The symptoms listed below can occur with prostate cancer (Most of the time these symptoms are caused by other prostate problems that are not cancer):
- Delayed or slowed start of urinary stream
- Dribbling or leakage of urine, most often after urinating
- Slow urinary stream
- Straining when urinating, or not being able to empty out all of the urine
- Blood in the urine or semen
- Bone pain or tenderness, most often in the lower back and pelvic bones (only when the cancer has spread)
Signs and tests
Prostate biopsy is the only test that can confirm the diagnosis. Tissue from the prostate is viewed underneath a microscope. Biopsy results are reported using something called a Gleason grade and a Gleason score.
The Gleason grade is how aggressive the prostate cancer might be. It grades tumors on a scale of 1 - 5, based on how different from normal tissue the cells are.
Often, more than one Gleason grade is present within the same tissue sample. The Gleason grade is therefore used to create a Gleason score by adding the two most predominant grades together (a scale of 2 - 10). The higher the Gleason score, the more likely the cancer is to have spread beyond the prostate gland:
- Scores 2 - 4: Low-grade cancer
- Scores 5 - 7: Intermediate- (or in the middle-) grade cancer. Most prostate cancers fall into this category.
- Scores 8 - 10: High-grade cancer (poorly-differentiated cells)
There are two reasons your doctor may perform a prostate biopsy:
- Your PSA blood test is high. See also: PSA
- A rectal exam may show a large prostate or a hard, irregular surface. Because of PSA testing, prostate cancer is diagnosed during a rectal exam much less often.
The PSA blood test will also be used to monitor your cancer after treatment. Often, PSA levels will begin to rise before there are any symptoms. An abnormal digital rectal exam may be the only sign of prostate cancer (even if the PSA is normal).
The following tests may be done to determine whether the cancer has spread:
The best treatment for your prostate cancer may not always be clear. Sometimes, your doctor may recommend one treatment because of what is known about your type of cancer and your risk factors. Other times, your doctor will talk with you about two or more treatments that could be good for your cancer.
In the early stages, talk to your doctor about several options, including surgery and radiation therapy. In older patients, simply monitoring the cancer with PSA tests and biopsies may be an option.
Prostate cancer that has spread may be treated with drugs to reduce testosterone levels, surgery to remove the testes, or chemotherapy.
Surgery, radiation therapy, and hormonal therapy can interfere with sexual desire or performance. Problems with urine control are common after surgery and radiation therapy. These problems may either improve over time or get worse, depending on the treatment. Discuss your concerns with your health care provider.
Surgery is usually only recommended after a thorough evaluation and discussion of the benefits and risks of the procedure.
- Surgery to remove the prostate and some of the tissue around it is an option when the cancer has not spread beyond the prostate gland. This surgery is called radical prostatectomy. It can also be done with robotic surgery.
- Possible problems after the surgeries include difficulty controlling urine or bowled movements and erection problems.
Radiation therapy uses high-powered x-rays or radioactive seeds to kill cancer cells.
Radiation therapy works best to treat prostate cancer that has not spread outside of the prostate. It may also be used after surgery, if there is a risk that prostate cancer cells may still be present. Radiation is sometimes used for pain relief when cancer has spread to the bone.
External beam radiation therapy uses high-powered x-rays pointed at the prostate gland.
- It is done in a radiation oncology center usually connected to a hospital. You will come to the center from home 5 days a week for the treatments. The therapy lasts for 6 -8 weeks.
- Before treatment, a therapist will mark the part of the body that is to be treated with a special pen.
- The radiation is delivered to the prostate gland using a device that looks like a normal x-ray machine. The treatment itself is generally painless.
- Side effects may include impotence, incontinence, appetite loss, fatigue, skin reactions, rectal burning or injury, diarrhea, bladder urgency, and blood in urine.
Prostate brachytherapy involves placing radioactive seeds inside the prostate gland.
- A surgeon inserts small needles through the skin behind your scrotum to inject the seeds. The seeds are so small that you don't feel them. They can be temporary or permanent.
- Brachytherapy is often used for men with smaller prostate cancer that is found early and is slow-growing.
- It also may be given with external beam radiation therapy for some patients with more advanced cancer.
- Side effects may include pain, swelling or bruising in your penis or scrotum, red-brown urine or semen, impotence, incontinence, and diarrhea.
Proton therapy is another kind of radiation used to treat prostate cancer. Doctors aim proton beams onto a tumor, so there is less damage to the surrounding tissue.
Testosterone is the body's main male hormone. Prostate tumors need testosterone to grow. Hormonal therapy is any treatment that decreases the effect of testosterone on prostate cancer. These treatments can prevent further growth and spread of cancer.
Hormone therapy is mainly used in men whose cancer has spread to help relieve symptoms. There are two types of drugs used for hormone therapy.
The primary type is called a luteinizing hormone-releasing hormones (LH-RH) agonist:
- These medicines block the body from making testosterone. The drugs must be given by injection, usually every 3 - 6 months.
- They include leuprolide, goserelin, nafarelin, triptorelin, histrelin, buserelin, and degarelix.
- Possible side effects include nausea and vomiting, hot flashes, anemia, lethargy, osteoporosis, reduced sexual desire, decreased muscle mass, weight gain, and impotence.
The other medications used are called androgen-blocking drugs.
- They are often given along with the above drugs.
- They include flutamide, bicalutamide, and nilutamide.
- Possible side effects include erectile dysfunction, loss of sexual desire, liver problems, diarrhea, and enlarged breasts.
Much of the body's testosterone is made by the testes. As a result, removal of the testes (called orchiectomy) can also be used as a hormonal treatment. This surgery is not done very often.
Chemotherapy and immunotherapy are used to treat prostate cancers that no longer respond to hormone treatment. An oncology specialist will usually recommend a single drug or a combination of drugs.
After treatment for prostate cancer, you will be closely watched to make sure the cancer does not spread. This involves routine doctor check-ups, including serial PSA blood tests (usually every 3 months to 1 year).
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. It is mostly affected by whether the cancer has spread outside the prostate gland and how abnormal the cancer cells are (the Gleason score) when you are diagnosed.
Many patients with prostate cancer that has not spread can be cured, as well as some patients whose cancer has not spread very much outside the prostate gland.
Even for patients who cannot be cured, hormone treatment can extend their life by many years.
The complications of prostate cancer are mostly due to different treatments.
Calling your health care provider
Discuss the advantages and disadvantages to PSA screening with your health care provider.
Following a vegetarian, low-fat diet or one that is similar to the traditional Japanese diet may lower your risk. This would include foods high in omega-3 fatty acids.
Finasteride (Proscar, generic) and dutasteride (Avodart) are drugs used to treat benign prostatic hyperplasia (BPH).
The American Society of Clinical Oncology (ASCO) and the American Urological Association (AUA) recommend that doctors discuss the pros and cons of these drugs with men who:
- Have a PSA score of 3.0 or below
- Are being screened yearly for prostate cancer
- Do not yet show signs of prostate cancer
Not all experts agree with this recommendation.
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.
Walsh PC. Chemoprevention of prostate cancer. N Engl J Med. 2010 Apr 1;362(13):1237-8.
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.
Reviewed By: Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.