The Medical Minute: Changing recommendations for prostate screening

By Dr. John Messmer

It used to be an annual ritual for men over 50 – a prostate check and a prostate specific antigen (PSA) blood test. Men and their doctors thought this annual screening test for prostate cancer was a good idea – find it early and treat it. After all, prostate cancer is the second leading cause of cancer deaths in men.

When PSA screening became widespread there was an increase in diagnosed prostate cancers. That would make sense – when you start looking for it, you are likely to find it. Part of the reason is that the presence of prostate cancer is fairly common as men age. Men have a 16 percent lifetime risk of developing prostate cancer, but most of these cancers do not become evident. Autopsy studies show that prostate cancer is present in two-thirds of men over age 80 and in one-third of younger men.

A man’s lifetime risk of dying from prostate cancer is just under 3 percent. His risk of dying from influenza or pneumonia is about the same from age 65-74 and three times that from age 75-84. His lifetime risk of dying from heart disease is 18 percent.

A test is termed “screening” when the problem being screened for is not known to be present but could be. Ideally a screening test for cancer should be positive when the cancer is present and negative when it’s not.

There are problems with the PSA test - there is no positive or negative. The result is a number – a measure of the amount of the chemical in the blood. When the number is really high, the man likely has prostate cancer, but when it’s only a little high, there are many other possible reasons for it. Plus, prostate cancer can be present with a low level of PSA. It’s just not a specific enough test for screening.

Treatment for prostate cancer can have unpleasant side effects: incontinence, pain on urination, erectile dysfunction, and hot flashes, for example. Even the biopsy of the prostate for diagnosis has risks.

Given the fact that prostate cancer is common but death from it is not that common, a biopsy proven prostate cancer might not cause a man’s death, particularly if he is older. So treatment may be more harmful than not doing anything. But how many people are comfortable knowing they have cancer but not treating it? Maybe it’s better not to look for it.

Those who treat prostate cancer point to a recent study in Europe that showed a statistically significant reduction in cancer deaths when men with PSAs over 3 are biopsied. However, more than 1,000 men need to be screened to prevent one cancer death; 37 total cancers would be found and presumably treated with no prevention of death. It is important to point out that there was no difference in total deaths from any reason between the screened group and the group that was not screened. This study means that while screening will find more prostate cancers, it makes no difference in death rates.

The United States Preventive Services Task Force has reviewed the evidence of benefit versus the potential harm of screening for prostate cancer and has made the recommendation that screening for prostate cancer with a PSA should not be done routinely in all men. That does not mean it should never be done at all. Each man has particular circumstances – family history, ethnicity, genetics, medical history – that make him unique.

Before having the PSA test, each man should discuss his personal risk factors with his physician to decide if it’s reasonable for him to have the test. It would be more appropriate for a healthy 45-year-old black man whose father died of prostate cancer at age 55 to have the test than for an older white man who has heart disease and diabetes and whose life expectancy is less than ten years.

There are other potentially more useful screening tests for men – diabetes, cholesterol, colorectal cancer, for example. Unless men get to their doctors, none of these things can be evaluated, so during Men’s Health Month, any man who has not checked in with his doctor in a while should do it.

John Messmer, M.D., is an associate professor of family and community medicine at Penn State College of Medicine and a staff physician at Penn State Milton S. Hershey Medical Center.

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Last Updated June 22, 2012