Health Illustrated Encyclopedia

Prostate cancer

Definition

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.

Alternative Names

Cancer - prostate

Causes

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 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 tumor size, any spreading outside the prostate (and how far), and how different tumor cells are from normal tissue. This is called staging. Identifying the correct stage may help the doctor determine which treatment is best.

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
  • Gleason score

Symptoms

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.

Additional symptoms that may be associated with this disease:

Exams and Tests

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.

Treatment

The appropriate treatment of prostate cancer is often controversial. Treatment options vary based on the stage of the tumor. In the early stages, talk to your doctor about several options, including surgery, radiation therapy, or, in older patients, monitoring the cancer without active treatment.

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 on either a temporary or permanent basis. Discuss your concerns with your health care provider.

SURGERY

Surgery is usually only recommended after thorough evaluation and discussion of all treatment options. A man considering surgery should be aware of the benefits and risks of the procedure.

  • Removal of prostate gland (radical prostatectomy) is often recommended for treatment of stage A and B prostate cancers. This is a lengthy procedure, usually done using general or spinal anesthesia. A surgical cut is made through the abdomen or perineal area. You may remain in the hospital for 5 - 7 days. Possible complications include impotence and urinary incontinence, although nerve-sparing procedures may reduce the risk of these complications. This surgery should be done by a urologist with extensive experience doing this specific procedure.
  • Orchiectomy alters hormone production and may be recommended for metastatic cancer. There may be some bruising and swelling initially after surgery, but this will gradually go away. The loss of testosterone production may lead to problems with sexual function, osteoporosis (thinning of the bones), and loss of muscle mass.

RADIATION THERAPY

Radiation therapy is used primarily to treat prostate cancers classified as stages A, B, or C. Whether radiation is as good as prostate removal is a debatable topic, and the decision about which to choose can be difficult. In patients whose health makes the risk of surgery unacceptably high, radiation therapy is often the preferred alternative. Radiation therapy to the prostate gland is either external or internal:

  • External beam radiation therapy is done in a radiation oncology center by specially trained radiation oncologists, usually on an outpatient basis. Prior to 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 resembles a normal x-ray machine. The treatment itself is generally painless. Side effects may include loss of appetite, fatigue, skin reactions such as redness and irritation, rectal burning or injury, diarrhea, cystitis (inflamed bladder), and blood in urine. External beam radiation therapy is usually done 5 days a week for 6 - 8 weeks.
  • Internal radiation therapy places radioactive seeds inside you, directly in or near the tumor. This is called brachytherapy. A surgeon makes a small cut in the area to inject the seeds. They are so small, you don't feel them. The seeds can be temporary or permanent. Because internal radiation therapy is directed to the prostate, it reduces damage to the tissues surrounding the prostate. Side effects may include pain, swelling or bruising in your penis or scrotum, red-brown urine or semen, impotence, incontinence, and diarrhea.
  • Radiation is sometimes used for pain relief when cancer has spread to the bone.

MEDICATIONS

Medicines can be used to adjust the levels of testosterone. This is called hormonal manipulation. Since prostate tumors require testosterone to grow, reducing the testosterone level often works very well in preventing further growth and spread of the cancer. Hormone manipulation is mainly used to relieve symptoms in men whose cancer has spread. Hormone manipulation may also be done by surgically removing the testes.

The drugs Lupron and Zoladex are also being used to treat advanced prostate cancer. These medicines block the production of testosterone. The procedure is often called chemical castration, because it has the same result as surgical removal of the testes. However, it is reversible, unlike surgery. The drugs must be given by injection, usually every 3 months. Possible side effects include nausea and vomiting, hot flashes, anemia, lethargy, osteoporosis, reduced sexual desire, and erectile dysfunction (impotence).

Other medications used for hormonal therapy include androgen-blocking agents (such as flutamide) which prevent testosterone from attaching to prostate cells. Possible side effects include erectile dysfunction, loss of sexual desire, liver problems, diarrhea, and enlarged breasts.

Chemotherapy is often used to treat prostate cancers that are resistant to hormonal treatments. An oncology specialist will usually recommend a single drug or a combination of drugs. Chemotherapy medications that may be used to treat prostate cancer include:

  • Adriamycin
  • Docetaxel
  • Estramustine
  • Mitoxantrone
  • Paclitaxel
  • Prednisone

After the first round of chemotherapy, most men receive further doses on an outpatient basis at a clinic or physician's office. Side effects depend on the drug given and how often and how long you take it. Some of the side effects for the most commonly used chemotherapy drugs for prostate cancer include:

  • Blood clots
  • Bruising
  • Dry skin
  • Fatigue
  • Fluid retention
  • Hair loss
  • Lowering of your white cells, red cells or platelets
  • Mouth sores
  • Nausea
  • Tingling or numbness in hands and feet
  • Upset stomach
  • Weight gain

MONITORING

You will be closely watched to make sure the cancer does not spread. This involves routine doctor's check ups. Monitoring will include:

  • Serial PSA blood test (usually every 3 months to 1 year)
  • Bone scan or CT scan to check for spreading of the cancers
  • Complete blood count (CBC) to monitor for signs and symptoms of anemia
  • Monitoring for other signs and symptoms, such as fatigue, weight loss, increased pain, decreased bowel and bladder function, and weakness

Support Groups

The stress of illness may be eased by joining a support group whose members share common experiences and problems. See support group - prostate cancer.

Outlook (Prognosis)

The outcome varies greatly, primarily because the disease is found in older men who may have a variety of other complicating diseases or conditions, such as cardiac or respiratory disease, or disabilities that immobilize or greatly decrease activities.

Possible Complications

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

When to Contact a Medical Professional

Call for an appointment if you are a man older than 50 who has:

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

You should discuss the advantages and disadvantages to PSA screening with your health care provider.

Prevention

There is no known prevention. Following a vegetarian, low-fat diet or one similar to the traditional Japanese diet may lower risk. Early identification (as opposed to prevention) is now possible by yearly screening of men over 40 or 50 years old through 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 does not always mean 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 pursue a PSA should be based on a discussion between patient and health care provider.

References

NCCN Clinical Practice Guidelines in Oncology: Prostate cancer. 1st ed. 2008. Accessed June 10, 2008.

Walsh PC, DeWeese TL, et al. Clinical practice. Localized prostate cancer. N Engl J Med. 2007;357(26): 2696-705.

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): 435-48.


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Review Date: 8/7/2008
Reviewed By: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California (6/10/2008).
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