Dr. Haddad is Geriatric Fellow, Division of Geriatric Medicine, Saint Louis University, Health Sciences Center, Saint Louis, MO.
Cancer of the prostate is the most common cancer in men. It is estimated that this disease will be diagnosed in almost 200,000 U.S. men in the year 2001 and will lead to the death of nearly 32,000. It is as controversial as it is widespread — there is no definite agreement among medical experts about screening, diagnosis or treatment for this disease.
A man's risk of getting prostate cancer increases with age and begins to rise sharply after age 50. Race makes a difference, although we do not know why. In white men with a history of prostate cancer in their immediate family and in all African-Americans, this upturn in risk begins at age 40. For all men, the probability of developing prostate cancer between ages 40-59 is 2.06% (1/49) and climbs to 13.4% (1/7) between age 60-79. African-Americans have a lifetime risk about 20% higher than the risk for white men and once they have the diagnosis they are, compared to whites, three times as likely to die from it.
Age and RaceAutopsy studies have shown that up to two-thirds of men develop prostate cancer, many without ever knowing it. Advanced age and African-American race are the strongest risk factors.
Family HistoryThe risk doubles if there is an immediate family member with prostate cancer. As the number of family members affected increases, the risk increases exponentially. Hereditary prostate cancer, although rare, does exist and occurs at an earlier age. There is no definite proof of an association between prostate cancer and fatty diet, vasectomy or sexually transmitted diseases.
The Stages of Prostate Cancer
Early-stage diseaseIn this stage there are normally no symptoms, as the disease is confined to part of the prostate gland. In some rare cases, however, early-stage prostate cancer can cause bladder outlet obstruction (difficulty passing passing urine to empty the bladder).
Locally advanced diseaseIn this stage, the cancer has advanced, but has not spread beyond the prostate itself. Bladder outlet obstruction is usually present. Other symptoms include bloody urine and urinary tract infections.
Metastatic diseaseIn this stage, the cancer has spread beyond the prostate gland and into other areas of the body. Common symptoms include bone pain, weakness in the legs (caused by pressure on the spinal cord), swelling in the lower legs from accumulated lymphatic fluid, and bladder and bowel sphincter dysfunction. When these symptoms are present, doctors should have an MRI done as soon as possible, as well as begin chemotherapy. In some cases, surgical or radiation therapy may be considered.
Screening and DiagnosisProstate cancer screening is probably the most controversial issue in the field of preventive medicine. Those who advocate early detection efforts cite data that show that 75% of patients with localized prostate cancer will move on to the locally advanced stage within 10 years and of these individuals 65% will die from cancer. Among patients with metastatic disease, nearly 50% will die within three years. In theory, at least, early detection can mean earlier effective treatment that cures the disease and maintains normal life expectancy without a great impact on quality of life.
Those who are against screening have pointed out that early detection, based on the research data currently available, does not seem to improve life expectancy. They have also argued that the prostate tumors detected earlier tend to be those that are more slow-growing; with or without detection, these would have not otherwise changed the natural course of life for that individual. All early detection accomplishes, they say, is to increase the time that a person is known to have such prostate cancer. Data from some very recent studies, while not conclusive, do seem to support the concept that early detection can save lives.
Digital rectal examination (DRE)This is the dreaded traditional rectal examination, in which a urologist or other physician uses his finger to test for the presence of swelling around the prostate gland. The National Comprehensive Cancer Control recommends an annual DRE for all men who are 50 or older, as well as higher-risk younger men. At the very least, DRE should be offered to men in these populations, along with an explanation of the how and why it is done. DRE can detect most, but by no means all, cases of prostate cancer.
PSA TestPSA is a substance naturally produced within the prostate and found in seminal fluid. Because PSA levels are increased by inflammation of the prostate, which can be caused by prostate cancer, testing for high PSA levels is a good way to detect at least the strong possibility of prostate cancer. While it is constantly being refined and improved, PSA testing has its limits, missing 18-25% of prostate cancer because of false negatives; it also produces false positive results approximately 60% of the time. It is inexpensive.
Current Recommendations on TestingAccording to the American Cancer Society 2001 guidelines for early cancer screening detection, DRE and PSA testing should be offered annually to men over the age of 50 who have a life expectancy of more than 10 years. Although today there is little strong evidence that these tests lower the death rate from prostate cancer, one recent survey showed that overall mortality in white men younger than 85 has declined compared to the years before PSA tests were routinely given.
Another group, the American College of Physicians/American Society of Internal Medicine (ACP-ASIM), recommends that doctor and patient share the decision whether or not to screen.
The U.S. Preventive Task Force, citing the lack of evidence for improved survival, has recommended against prostate cancer screening.
BiopsyDepending on the results of the DRE and PSA test, the next step is a biopsy, which means taking a small sample of tissue from the prostate for examination. Possible side effects from this prodedure include infection, bloody urine and blood in the stool.
The Prognosis and Spread of Prostate CancerProstate cancer can be extremely slow developing. Statistics from autopsies show that 30% of men in their 70s, 40% in their 80s and 50% in their 90s had prostate cancer. Most, of course, died from something else.
The disease metastisizes (spreads) in three ways. The first is by moving directly into the tissues around the prostate; the second is via the lymph system to the lymph nodes; and the third is through the bloodstream into the bones. Only rarely does prostate cancer spread to the liver or lungs.
Age, overall health and above all how far the disease has progressed are the most important factors in determining life expectancy and likelihood of survival.
TreatmentIn January 2001, NCCN (The National Comprehensive Cancer Network) issued a set of treatment guidelines. The NCCN recommended starting by determining the risk that the disease will recur. This is done by dividing prostate cancer cases into low, intermediate and high likelihood groupings. In the low group, the recommended treatment is observation and careful follow-up. In patients with a life expectancy of more than 20 years, either radical prostatectomy (removal of the entire prostate gland) or external radiation seem to be the options with the highest chance of complete cure. No difference in later quality of life has been observed between the two.
In the intermediate risk group, the recommended choice is between radical prostatectomy and external radiation. If the patient's life expectancy is less than 10 years, then observation alone may be the best option.
When the risk of recurrence is deemed high, then hormone therapy, hormone therapy plus radiation or, in selected patients, radical prostatectomy are the best treatment options. If life expectancy is 10 years or less, observation alone may be the appropriate choice.
In cases of metastatic disease, hormone therapy is advised.
Life expectancy needs to be considered when determining treatment because, as discussed above, there is always the chance — even the likelihood — that the patient will ultimately die from something else. Another important consideration is the possibility that treatment will cause impotence or other unpleasant problems. In treating prostate cancer, the goal is to be realistic. Adding life to years may be a better strategy than adding years to life.
Radical Prostatectomy (RP)Studies have found no evidence that, for most people, RP improves survival in comparison with less radical treatment (such as radiation) and careful follow-up. While there is limited evidence that surgery does reduce the risk of metastasis compared to radiation, RP carries the same health risks as other major surgeries. There are also some problems specific to RP, including sexual dysfunction (occurring in over 80% of patients), urinary incontinence (30%), urethral stricture (18%), fecal incontinence (5%) and others.
External Beam Radiation (EBR)For most people, EBR is as effective a treatment for prostate cancer as RP, although there is a slightly higher risk of metastasis. Complications include impotence in 20-30% of patients, bowel dysfunction in 10% and urinary incontinence in 7%. Up to one-third of patients whose cancer is at an early stage and limited to the prostate gland itself are still cancer-free three years after treatment. The overall survival rate is estimated to be 85%.
In cases where metastasis has already taken place, the role of EBR is limited to providing a good measure of pain relief. There are other risks associated with EBR that should be discussed on a case-by-case basis with a doctor.
Androgen Deprivation Therapy (ADT)In patients with prostate cancer that has spread to the lymph nodes, a combination of ADT, which involves lowering the amount of naturally occurring male hormones within the body, and RP has been shown to improve survival and reduce the risk of recurrence. After metastasis has occurred, ADT improves symptoms, but does not seem to make a difference in mortality. Possible complications include problems with constriction or dilation of the blood vessels, loss of libido, swelling of the breasts, weight gain, osteoporosis and loss of muscle mass.
ChemotherapyChemotherapy decreases pain and discomfort in some men with prostate cancer. It makes no difference as far as survival rates are concerned. Serious complications are rare.
ConclusionWhile better treatments are improving the prognosis for men with prostate cancer, there are great differences of opinion within the medical community about the diagnosis, screening methods and treatment for this difficult disease. For this reason alone, it is important for all men to educate themselves about this disease and stay informed about new treatments and screening methods. It is currently recommended that all men over 50 should consider discussing screening for prostate cancer with their doctor. Certainly any man who has significant risk factors or who suspects that he might have some symptoms should see a doctor immediately.