USELESS USE OF PSA

Although prostate-specific antigen (PSA)-based screening for prostate cancer in the United States has declined after the release of 2012 guidelines discouraging the practice, large numbers of high-mortality-risk men are still being screened unnecessarily.

A new study, the first to report national data, shows that although the overall proportion of men undergoing PSA screening has declined significantly since the guidelines were introduced, almost 1.5 million men aged 65 years with a more than 52% risk for 9-year mortality were screened in 2013.

The research was presented at the recent annual meeting of the American Society of Clinical Oncology, and was published online June 8 in the Journal of Clinical Oncology.

Study author Scott E. Eggener, MD, from the University of Chicago Medical Center in Illinois, explained that PSA testing was introduced in the late 1980s and early 1990s. "[I]ntuitively thinking, it was a great idea to identify cancers at an early curable stage," he noted.

However, conflicting data as to the potential value of PSA screening soon emerged from randomized trials in the United States and Europe.

Dr Eggener said: "There's a huge problem of overdiagnosis and overtreatment; basically, diagnosing men with prostate cancers that were never going to cause them problems."

In response, the US Preventive Services Task Force released guidelines in 2012 discouraging PSA screening, as the benefits were judged to be far smaller than the potential harms.

To examine the effect of these guidelines on practice, Dr Eggener and colleagues used data from the nationally representative National Health Interview Survey to determine the proportion of men aged 40 years and older who saw a physician and were screened for prostate cancer.

Specifically, screening rates in 2005, 2010, and 2013, involving 8490, 7326, and 9803 men, respectively, were compared with logistic regression analysis, and a 9-year mortality index was used to analyze screening rates based on life expectancy.

Between 2010 and 2013, PSA screening rates declined significantly among men aged 50 to 59 years, those aged 60 to 74 years, and those aged 75 years or older, dropping from 33.2% to 24.8% (P < .01), 51.2% to 43.6% (P < .01), and 43.9% to 37.1% (P = .03), respectively.

Screening rates did not, however, decrease significantly among men aged 40 to 49 years during the same period, going from 12.5% to 11.2% (P = .4).

"The men in their 40s is somewhat of a unique scenario, where there's not a lot of data to go on regarding the pros and cons of screening," Dr Eggener commented to Medscape Medical News.

"My sense was men in their 40s, either on their own or with their doctor...were just choosing to do it, regardless of what these recommendations showed," he said.

The results also showed that large numbers of men were screened for prostate cancer in 2013 despite having a more than 52% risk for 9-year mortality, at 27.2% of those aged 65 to 69 years, 32.3% of those aged 70 to 74 years, and 32.2% of those aged 75 years or older. Overall, the team estimates that approximately 1.4 million high-mortality-risk men aged 65 years and older were screened in 2013.

Discussing the implications of the findings, Dr Eggener observed that "we could talk for hours on the pros and cons of PSA screening."

He added: "My personal belief based on the data is that screening can save lives, and when we screen smartly, it's a very powerful tool. That's one side of the story.

"The other side, which I also agree with, is that there's been a pandemic of screening too many men that are older or sicker, and that's not smart screening patterns. You can cause a lot more harm in those men than good."

Dr Eggener cautioned: "Unfortunately what this data shows is that, in the United States, the older, sicker men are still being screened at a much higher rate than the much healthier men. I'd like to see the exact opposite."

He pointed out that there are two newer screening tests available, including the 4K score and the Prostate Health Index, which perform better than PSA screening. However, these tests also have issues: As previously reported by Medscape Medical News, the Prostate Health Index was deemed unlikely to improve diagnostic accuracy in clinical practice by the National Institute for Health and Care Excellence, the United Kingdom's healthcare watchdog.

Dr Eggener concluded: "The other big piece of information is that, once a man is diagnosed with prostate cancer, it used to be the case that nearly every man that was diagnosed underwent treatment."

"We now know through a bunch of great data that there are many men with small, nonaggressive prostate cancers that we can closely keep an eye on, and not necessarily treat right away, using the active surveillance approach," he added.

Dr Eggener declared the following: consulting or advisory role: Myriad Genetics, Medivation, Janssen Pharmaceuticals, Genomic Health, OPKO Diagnostics, and MDx Health; speakers' bureau: Myriad Genetics and Janssen Pharmaceuticals Research; and funding: Myriad Genetics. The other authors have disclosed no relevant financial relationships.

J Clin Oncol. Published online June 8, 2015. Abstract