Is 1.5 the new magic number for PSA screening?

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A new approach to prostate cancer screening has been proposed by investigators who claim the idea of informed decision-making by primary care physicians is not working when it comes to PSA testing.

A new approach to prostate cancer screening has been proposed by a group of investigators who claim the idea of informed decision-making by primary care physicians is not working when it comes to PSA testing.

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In their paper, which was published in Urology (2016; 96:116-20), the authors suggest that men 73 years of age and younger who have a PSA below 1.5 ng/mL should have a follow-up test in 5 years, but those above that number should be referred to a urologist for further screening.

“We need a simple message to primary care doctors-who do 90% of PSA testing in the U.S.-about what is abnormal and what is normal,” first author E. David Crawford, MD, of the University of Colorado, Denver, told Urology Times. “When it comes in below 1.5, it gives them that simple message. The second message is that we can identify a danger zone and when you’re in that danger zone, you go to the next level of testing to try and rule in or rule out prostate cancer.”

The reasoning is that screening with PSA has limitations. A large percentage of men who do not have prostate cancer will screen positive and require a biopsy to rule out cancer, whereas a few with aggressive disease have low PSA. Since many prostate cancers grow so slowly that they never threaten a patient’s life, there is a danger of overtreatment if these cancers are detected. This is an especially important issue because treatment for prostate cancer is often associated with significant side effects.

Dr. Crawford noted that in 1989, when prostate cancer became the most common cancer diagnosed in men and the second leading cause of death for men, most of the patients with prostate cancer were cases that were advanced and incurable.

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He helped start Prostate Cancer Awareness Week, and it became what he called “almost too successful” in that screening occurred so much that advanced disease was just about eliminated from the equation and it created an issue where doctors were sticking needles in prostates because men had an elevated PSA most likely due to an enlarged prostate from BPH.

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“We put ourselves in a situation where we thought we were doing the right thing, but it became clear to a lot of us that we were over-diagnosing and over-treating prostate cancer,” he said. “The rub here is that urologists and people who evaluate need to be good citizens. Most commonly, it’s just an enlarged prostate. We have tests that help us discriminate who has aggressive prostate cancer, and that’s what we want to find.”

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The paper also noted that an elevated PSA is a surrogate for an enlarged prostate. If a man has an enlarged prostate, he is on a slippery slope, so after evaluation, that needs to be treated early as well.

According to Dr. Crawford, physicians need to avoid PSA tests in men who would have little to no gain by focusing on age and health, and the emphasis going forward should be finding the more aggressive cancers while avoiding biopsy in those at low risk or those with indolent disease.

“We need to get away from the one-size-fits-all approach used for screening in the past, and use PSA more intelligently for more personalized decisions,” he said. “We feel this is the right step to aid family practice doctors so they can do the best to help men and find men that have prostate cancer that needs to be evaluated and treated.”

Dr. Crawford serves as a speaker for Beckman Coulter, Genomic Health, and MDx Health.