A PSA about Inappropriate PSA Screening

psaThere’s no denying that preventive medical screens do save lives, whether through mammograms, colonoscopies, or prostate exams. But for all the benefits, screening is not a one-size-fits-all practice. In the case of prostate cancer, mortality rates have declined by more than 30 percent in the last 20 years as testing levels of prostate-specific antigen (PSA) became a common clinical screen in older men. But other studies of the benefits of PSA screening have been less decisive, including a large 2009 study that found no difference in cancer-specific mortality over the last 10 years. Why the discrepancy?

One answer is that the benefit of PSA screening changes with age – and the reduced life expectancy that comes with age. Though 1 in 6 men will be diagnosed with prostate cancer at some point in their lives, many older men diagnosed with prostate cancer die of something other than the disease. Screening elderly men who already have serious health problems can therefore do more harm than good, paving the way for invasive procedures, risky treatment, anxiety, and health care costs that may have been unnecessary. As a result, many clinical panels have recommended that PSA screening should only be conducted in men younger than 75 or men with at least 10 years of estimated life expectancy due to old age or health problems.

But recommendations do not always match up with practice. To measure the true screening patterns in the clinical setting, a team including Scott Eggener, assistant professor of surgery at the Medical Center, broke down the numbers from a huge national health survey. The data , published this week in the Journal of Clinical Oncology, showed a quite different shape than many would hope: rather than a bell curve with the highest screening rates appearing in men 55-69 who benefit the most, the curve is an uphill climb to a plateau, with men in their 70s receiving the most tests. Men aged 70 to 79 were screened for PSA at almost twice the rate of men aged 50 to 54.

“Our findings show a high rate of elderly and sometimes ill men being inappropriately screened for prostate cancer,” Eggener told John Easton. “We’re concerned these screenings may prompt cancer treatment among elderly men that ultimately has a very low likelihood of benefiting the patient and paradoxically can cause more harm than good.”

When measured according to life expectancy, the results were not much better. Roughly 750,000 men with an estimated life expectancy of 5 years – half of the recommended 10 years – received PSA screening in the previous year.

“The men most likely to benefit from PSA screening are paradoxically being screened at markedly lower rates than men highly unlikely to benefit,” the authors wrote.

Many reasons may exist for the over-screening in elderly men. Doctors may be over-confident in the value of screening, or may not accurately estimate life expectancy in their patients. Patients motivated to seek out screening by awareness and fund-raising efforts such as Major League Baseball’s Home Run Challenge or free screening days may not understand the nuances of when those screens are most appropriate. There’s also the simple fact that older men have more health issues and visit the doctor’s office more frequently, creating more opportunities for PSA testing.

The conclusions of the paper echo comments made at the University of Chicago last fall by American Cancer Society chief medical and scientific officer Otis Brawley, who spoke out against the high medical and financial costs of indiscriminate prostate cancer screening. Even the man who first discovered PSA has come out against over-screening, writing in the New York Times that he “never dreamed that my discovery four decades ago would lead to such a profit-driven public health disaster.” But it’s important to remember that PSA screening does retain its usefulness when used in the right circumstances, and asking the right questions in the doctor’s office is important for any male patient.

“The optimal way of doing it is for both patients and physicians to have a meaningful conversation about, ‘should I get this test or should I not?'” Eggener told Reuters. “Those younger men are the ones the test was designed for.”

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Drazer, M., Huo, D., Schonberg, M., Razmaria, A., & Eggener, S. (2011). Population-Based Patterns and Predictors of Prostate-Specific Antigen Screening Among Older Men in the United States Journal of Clinical Oncology DOI: 10.1200/JCO.2010.31.9004

About Rob Mitchum (526 Articles)
Rob Mitchum is communications manager at the Computation Institute, a joint initiative between The University of Chicago and Argonne National Laboratory.
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