Prostate cancer involves a malignant tumor growth within the prostate gland.
Causes, incidence, and risk factors
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 regress. 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 black men older than 60, farmers, tire plant workers, painters, and men exposed to cadmium. The lowest incidence occurs in Japanese men and vegetarians.
Prostate cancers are classified or staged based on their aggressiveness and how different they are from the surrounding prostate tissue. 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:
- A: Tumor is not palpable (not felt on physical examination), and is usually detected by accident after prostate surgery done for other reasons.
- B: Tumor is confined to the prostate and usually detected by physical examination or PSA testing.
- C: Tumor extends beyond the prostate capsule without spread to lymph nodes.
- D: Cancer has spread (metastasized) to regional lymph nodes or other parts of the body (bone and lungs, for example).
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
- Bone pain or tenderness
- Hematuria (blood in the urine)
- Abdominal pain
- Unintentional weight loss
Signs and tests
A rectal exam often reveals the hard, irregular surface of an enlarged prostate.
- PSA (prostate specific antigen, a blood test) may be elevated, although other conditions such as BPH can cause the PSA to rise.
- Free PSA may be more specific in differentiating BPH from prostate cancer.
- Urinalysis may reveal blood in the urine.
- Urine or prostatic fluid cytology may reveal atypical cells.
- A prostate biopsy confirms the diagnosis.
- CT scans may be performed to rule out metastasis (spread of the cancer).
- A bone scan may be performed to rule out metastasis.
- Chest x-ray may be performed to rule out metastasis.
A newer test called AMACR is more sensitive for determining the presence of prostate cancer than the PSA test and may soon be more widely used to diagnose disease.
The appropriate treatment of prostate cancer is often controversial. Treatment options vary based on the stage of the tumor. In the early stages, surgical removal of the prostate (prostatectomy) and radiation therapy may be used to eradicate the tumor. Metastatic cancer of the prostate may be treated by hormonal manipulation (reducing the levels of testosterone by drugs or removal of the testes) or chemotherapy.
Surgical treatment is usually only recommended after thorough evaluation and discussion of treatment options. A man considering surgery should be aware of the expected benefit of the procedure, as well as its potential risks.
- Removal of prostate gland (radical prostatectomy) is often recommended for treatment of localized stage A and B prostate cancers. This is a lengthy procedure, usually performed using general or spinal anesthesia. An incision is made through the abdomen or perineal area. You may remain in the hospital for 5 to 7 days. Possible complications include impotence and urinary incontinence, although nerve-sparing procedures may reduce the risk of these complications. This surgery should be performed 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 subside. The loss of testosterone (hormone) production may lead to problems with sexual function, osteoporosis (thinning of the bones), and loss of muscle mass.
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 may be performed in a number of ways:
- External beam radiation therapy is performed in a radiation oncology center by specially trained radiation oncologists, usually on an outpatient basis. Prior to treatment, a therapist will mark the location that is to be radiated with a special semi-permanent marking 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. However, there are several side effects associated with radiation therapy - 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 performed 5 days a week for 6 - 8 weeks.
- Another method consists of implanting small pellets of radioactive iodine, gold, or iridium directly into the prostate tissue through a small incision. The advantage of this form of radiation therapy is that the radiation is directed at the prostate with less damage to the surrounding tissues.
- Radiation is sometimes used for pain relief when cancer has spread to the bone.
Hormonal manipulation aims at lowering testosterone levels. Since prostate tumors require testosterone, reducing the testosterone level is often very effective in preventing further growth and spread of the cancer. This can be done either through surgical removal of the testes or by using medications. Hormone manipulation is mainly used to relieve symptoms in men whose cancer has spread. Preliminary evidence suggests that it may improve cure rates when combined with radiation or surgery. However, this is still under investigation.
Synthetic drugs like Lupron or Zoladex that mimic the function of LHRH (luteinizing hormone releasing hormone) are being used increasingly to treat advanced prostate cancer. These medications suppress testostorone production. The procedure is often called chemical castration, because it has the same result as surgical removal of the testes, although 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 aimed at destroying the cancer cells. Medications that may be used to treat prostate cancer include:
Most men receive their chemotherapy (after the initial dose) on an outpatient basis at a clinic or physician’s office. Possible side effects are numerous and specific to a given chemotherapy drug.
Surgery, radiation therapy, and hormonal manipulation all have the potential to disrupt sexual desire or performance on either a temporary or permanent basis. Discuss your concerns with your health care provider. Additionally, several options are available for managing sexual problems related to prostate cancer treatment.
You will be closely monitored for progression of the disease regardless of the type of treatment you receive. Monitoring will include:
- Serial PSA blood test (usually every 3 months to 1 year)
- Bone scan or CT scan to evaluate for metastasis
- Complete blood count (CBC) to monitor for signs and symptoms of anemia
- Monitor for other signs and symptoms indicating disease progression, such as fatigue, weight loss, increased pain, decreased bowel and bladder function, and weakness
The stress of illness may be eased by joining a support group whose members share common experiences and problems. See support group - prostate cancer.
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.
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.
Calling your health care provider
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 maintained annual evaluations
- A family history of prostate cancer
You should discuss the advantages and disadvantages to PSA screening with your physician.
No preventive measures are known. Adopting a vegetarian, low-fat diet or one that mimics 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 elevated PSAs do not always mean a patient has prostate cancer. The second is that physicians 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 physician.
September is Prostate Cancer Awareness Month in the US. Several urology centers across the country hold screening clinics that provide free rectal exams and PSA blood testing. Contact a hospital or medical center in your area for information on its program for prostate cancer awareness.
by Gevorg A. Poghosian, Ph.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.