Ask the Doctors

Dear Doctor: I have read that screening guidelines for prostate cancer are changing again. Why does this keep happening, and why should I believe the latest guidelines if they're just going to be rewritten in a couple of years?

Dear Reader: By its very nature, medicine is an ever-advancing discipline. Findings from new and ongoing research not only push the frontiers of understanding, but they also cast light on what is already known. As a result, the latest information gets incorporated into present-day medical practice. This leads to continual -- and sometimes unsettling -- change.

Let's start with what a screening test actually is.

Unlike diagnostic tests, which are performed to pinpoint the reason for specific symptoms, screening tests are performed in individuals who feel well. Their purpose is to catch a disease or condition in its earliest stage, when it is easiest to treat or manage. Hearing tests, mammograms, pap smears, colonoscopies, blood cholesterol levels, urinalysis, HIV tests -- all are examples of various screening tests performed for different reasons.

You're right when you say that screening recommendations seem to be always changing. The recent history of prostate cancer screening can help explain why.

The PSA test, or prostate-specific antigen test, was once routinely used to screen for early-stage prostate cancer. It's a test that measures the level of a certain protein in a man's blood, which can be an indicator of prostate cancer. But elevated PSA levels may also be the result of benign enlargement of the prostate, or an inflamed prostate due to an infection. It can also be the sign of a very slow-growing cancer. This meant that men with elevated PSA levels often underwent invasive procedures like biopsies even when they did not have prostate cancer, or when their disease was growing so slowly that it would never cause symptoms.

Although some patients were helped by PSA testing, the data showed that many underwent treatment without benefit. This led to new screening guidelines in 2008, and again in 2012. To prevent men from having unnecessary procedures, it was recommended that men within certain age groups rely on active surveillance rather than the PSA test to detect prostate cancer.

Now, though, new data and additional studies suggest the need for a higher level of vigilance. As a result, further changes to prostate screening guidelines are under consideration.

If approved, the new guidelines will recommend that men between the ages of 55 and 69 talk to their physicians about whether a PSA test is appropriate for them. They should also discuss how frequently the test should be performed. Risk factors like age, race, lifestyle, family history, environmental factors and inherited gene mutations will play a part in this shared decision-making process.

Despite the confusion that can result from these changing guidelines, we believe that screening is important. The test results, when put into the context of years, create a valuable timeline. And when done properly and appropriately, the right test at the right time can save your life.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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