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Screening for prostate cancer? Patients should decide

By Otis W. Brawley, Special to CNN
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STORY HIGHLIGHTS
  • American Cancer Society has new guidelines on screening for prostate cancer
  • Dr. Otis Brawley says they leave it up to men to decide whether to take test
  • Studies differ on whether screening saves lives, he says
  • Brawley says it's clear that prostate cancer screening leads to some unnecessary treatment
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Editor's note: Otis W. Brawley is chief medical officer of the American Cancer Society and professor of hematology, oncology, medicine and epidemiology at Emory University.

Atlanta, Georgia (CNN) -- This week, the American Cancer Society releases updated prostate cancer screening guidelines. The guidelines say "men should discuss the uncertainties, risks and possible benefits of screening for prostate cancer before deciding whether to be tested."

With this update, a group of experts in urology, oncology, epidemiology and treatment outcomes and patients states clearly that a man needs to know the facts about prostate cancer screening and then needs to make a decision that is right for himself. It is not a statement against screening, but it is not a statement for screening either.

One can reasonably ask, how did we get into this quandary? The answer is, we became unscientific. We began promoting and using the prostate-specific antigen test before it had been adequately evaluated. This is a common practice in American medicine and a major reason for its expense.

In many ways, the new guidelines are very similar to the cancer society's prostate screening guidelines issued in 1997 and 2001. These guidelines also called for the physician and patient to engage in shared decision-making. Other organizations in the U.S., Canada, Europe and Australia that issue prostate cancer screening guidelines have also issued statements calling for informed or shared decision making.

Read more about the change in the guidelines

There are legitimate questions as to whether prostate cancer screening saves lives, and there is clear evidence that it leads to unnecessary treatment. Even after the long-awaited reports of two large long-term clinical trials designed to answer the question, we still have uncertainties.

This may be news to many who regularly read or hear reports suggesting that prostate cancer screening is beneficial. The benefits of prostate cancer screening have often been overstated. Some, often with a financial interest, even note that screening increases the five-year survival rate, which is true. They fail to say that the true evidence of a benefit to screening is not the finding of an increase in five-year survival; the true evidence of a benefit to screening is demonstration of a decrease in risk of death (or mortality).

Two clinical trials published in 2009 aimed to answer that question. To be fair, both trials have flaws, but rarely is a clinical trial perfect.

One trial, done in Europe, found that screening and aggressive treatment reduced relative risk of death by 20 percent, but it also found that 48 men had to be diagnosed and treated to save one life about 10 years later.

An American trial did not find a decrease in risk of death.

Both trials continue, and we all hope that a true benefit to our current screening technologies is found. It is worth noting that both of these trials and several previous studies show that screening increases risk of prostate cancer diagnosis and therefore treatment. It is a certainty that men who choose to be screened increase their risk of receiving needless treatment.

It is my belief that these guidelines hit the mark, that men who are concerned about prostate cancer should seek the counsel of a physician, discuss their health situation and make a decision as to whether they should be screened.

I also believe there are some men who, confronted with the facts about screening, will be concerned about being diagnosed and treated for a cancer that will never kill them. The risks of screening are proven; the benefits are less certain. Prostate cancer treatment is associated with serious side effects. These men may choose not to undergo screening. Both choices are reasonable.

What is known about prostate cancer and our current screening tests:

• Prostate cancer is a significant cause of cancer death. It is the second leading cause of cancer death in men, behind lung cancer and just ahead of colon cancer.

• The only study to adequately evaluate how good our current screening tests are at finding prostate cancer found that seven years of annual screening misses as many cancers as are found.

• A number of studies show that screening finds a large number of cancers, far more than the number of men destined to die of prostate cancer.

A 50-year-old man who chooses to be screened definitely doubles his risk of prostate cancer diagnosis from a lifetime risk of about 10 percent to a lifetime risk of about 20 percent. The European trial suggests that he may lower his risk of death by 20 percent, from a lifetime risk of 3 percent to a lifetime risk of 2.4 percent.

The above facts lead to the conclusion that we desperately need better screening tests that can lead to lives saved with less collateral damage. We desperately need a test that distinguishes the kind of disease that needs treatment from the kind of disease that will never kill but needs to be watched. Until these tests are developed, men should decide on screening based on their personal concerns and enter the clinical studies to help find out how good screening is and to help find better tests.

Ironically, the overpromise in the promotion of prostate cancer screening has prolonged the uncertainties and slowed our progress in prostate cancer medicine by dissuading men from entering studies to improve screening.

The opinions expressed in this commentary are solely those of Otis W. Brawley.

The full ACS statement is available here.