Apr 14,2009 00:00
Though the debate over screening for prostate cancer has been brewing for years, new information further questions the role of the prostate-specific antigen test in preventing death from prostate cancer.
Recently, two major articles published in The New England Journal of Medicine seriously question the value of the PSA test.
The first study followed 76,693 men from 10 U.S. medical centers. Half the patients received PSA tests annually, and the others did not. After seven years, analysis showed that measuring PSA did not significantly reduce the death rate from prostate cancer. The second study followed 182,000 men in Europe and showed that the tests had a similarly low impact on the number of prostate cancer deaths.
The problem with the PSA test is that elevated results often lead to tests and invasive procedures that may not be warranted. For every 12 elevated PSA levels, biopsies of prostates reveal only three instances of prostate cancer. The biopsy process involves inserting a needle into the prostate gland 12 times to remove a small piece of prostate tissue. Between the pain and the potential risk of bleeding, many men certainly would be much happier to avoid biopsies altogether.
If prostate cancer is diagnosed in a patient, he usually is treated by a prostatectomy (having his prostate removed), which can be done with irradiation or by implanting radioactive seeds in the prostate. After treatment, many of these patients are placed on medications to remove testosterone (also known as chemical castration). These procedures have many side effects, including impotence and urinary incontinence. In some cases, stomach pain, diarrhea or constipation occurs. And evidence suggests that in many men, aggressive treatment is not warranted.
Based on all these facts, should we stop screening for prostate cancer? The answer is definitely no. More than 26,000 men die of prostate cancer every year, and detecting cancer early can lead to curing it. Prostate cancer is serious in young men, black men and in those with strong family histories of prostate cancer.
Some cancers are far more aggressive than others. How aggressive a particular cancer is can be determined by examining the cancer cells under a microscope. Pathologists rank the aggressiveness of cancers with the Gleason scale, which scores tumors from 1-10. Tumors with scores of 7 or higher need to be treated aggressively. Tumors that score less than 5 can be approached more conservatively.
We must continue to screen for prostate cancer, but our approach must change. The PSA test is simply too inaccurate for us to investigate every patient with an elevated result. Many things cause PSA levels to be abnormally high, including a very large prostate, recent sexual activity and prostatitis. Also, if a physician has done a digital rectal examination immediately before obtaining blood for the measurement, it's possible for the level of PSA to be abnormally high. An elevated PSA level does not necessarily require an immediate referral to a urologist for a prostate biopsy.
With all the mounting evidence against PSA screening, here is the most rational approach: For men between the ages of 40 and 70, PSA measurements should be obtained every one or two years. The U.S. Preventive Services Task Force does not recommend PSA measurements in men older than 75; some experts state that it is of no value for a man who is 70 or older. Screening also should include an annual digital rectal examination. That can identify very hard nodules, which may indicate the presence of a cancer.
If the PSA level is moderately high, the test should be repeated after three months, six months and one year. If the level remains stable, increases only minimally, or decreases, no further investigation is warranted. However, if the PSA level increases rapidly or is very high (greater than 15), a referral to a urologist for a biopsy is warranted. If the biopsy reveals a tumor with a high Gleason score, prostatectomy is the treatment of choice. Some may recommend irradiation or radioactive seeds, but treatment definitely is warranted. If the Gleason score is low, wait watchfully; more PSA measurements may be needed.
By being rational and taking sound scientific evidence into account, screening for prostate cancer can be done appropriately, without undue procedures. This is the best way to ensure the most appropriate, rational and financially viable care.
Dr. David Lipschitz is the author of the book "Breaking the Rules of Aging."
Copyright 2009 Creators Syndicate Inc.