In 2012, the US Preventive Services Task Force made clear its opinion on prostate-specific antigen (PSA) screening for prostate cancer. Their recommendation: “Do not use prostate-specific antigen-based screening for prostate cancer.”
They graded the test a “D,” which means there is “moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.”
There is no grade “F.”
Four years earlier, in 2008, the task force was more forgiving. It concluded that one group, men over 75, should not be screened, but that there was not enough evidence to recommend either way with confidence for men younger than 75.
This recommendation had little impact on the numbers of men getting screened, even among men over age 75.
But the 2012 recommendations, published May 21, 2012, had more data and a simpler message. Two large clinical trials of PSA screening were published after 2008. One (PLCO) showed no advantage to screening. The other (ERSPC) found a 20 percent decrease in risk of death from prostate cancer. They also confirmed the frequent false-positive results of PSA tests, which often lead to more testing, including biopsies, which come with potential risks.
Men of all ages who are diagnosed with prostate cancer tend to choose surgery, radiation, or hormone therapy over watchful waiting, the task force argued, all of which can have side effects such as urinary incontinence and erectile or bowel dysfunction.
So Scott Eggener, MD, a urologic surgeon and prostate cancer specialist at the University of Chicago, and colleagues Michael Drazer and Dezheng Huo, decided to see if the new guidelines were being ignored, followed or misinterpreted. They found all three.
Their study, published June 8, 2015, in the Journal of Clinical Oncology, “was the first paper to look at the recent national impact,” Eggener said, “and it was substantial.”
The researchers used data from the National Health Interview Survey, a face-to-face, computer-assisted annual survey overseen by the Centers for Disease Control and Prevention and the U.S. Census Bureau. It analyzed screening rates from 2005, 2010 and 2013.
From 2005 to 2010 there was no real change in screening rates. The 2008 task force guidelines were widely ignored.
From 2010 to 2013—one year after the 2012 announcement—the guidelines began to have an impact. Far fewer men were being screened. The biggest change came in men aged 50 to 59, where relative screening rates fell by 25 percent.
This raised some concerns. This age group “has the most to gain and the most to lose from screening,” Eggener said. Even the guidelines note that the optimal age range for screening is from age 55 to 69.
Many individuals in their 50s or 60s who were correctly diagnosed early have clearly benefited from treatment. They lucky ones live cancer-free for a long time and then die of something else. The unlucky ones—those who were misdiagnosed, whose cancers would probably have remained asymptomatic, or who were harmed by treatment they may not have needed—did not get quite the same benefit. Some got no benefit, or worse.
“A substantial percentage of men who have asymptomatic cancer detected by PSA screening have a tumor that either will not progress,” the guidelines explain, “or will progress so slowly that it would have remained asymptomatic for the man’s lifetime.”
In their paper, the researchers weigh the odds and consider various alternative screening models—middle of the road approaches between screening annually or never—such as PSA screening every three to five years.
Why would that help? Prostate cancers tend to grow slowly. Some hardly grow at all. PSA screening can detect small cancers years before they cause symptoms, much less serious illness or death. So less frequent screening could reduce overdiagnoses by 27 percent and false positives by 50 percent, according to one statistical model, yet still prevent 83 percent of the prostate cancer deaths that would have been caught by annual screening. That proposal, offered in 2013, has not caught on.
There was one clear take-home message, however, that did reach consensus. “Way too many older sicker men, those over age 75 or those with life expectancy less than nine years, are still getting screened,” Eggener said. PSA testing may be a contentious issue, but “on this, we all agree. This group is clearly being overtested, with little chance of benefit.”
For example, in 2013, an estimated 1.4 million men in the U.S. over age 65 with a high probability of death within nine years got screened. Why does this continue? Shouldn’t physicians offer advice, stop offering the test, shepherd these men through their choices, follow the guidelines?
“I don’t know,” Eggener said. “I just don’t know. We aren’t reaching this group,” he added. “Maybe we need a PR campaign. At its core this is a complex, frustrating issue, but at the fringes, which include men over 75, we need to stop the madness.”