It was among the government’s most controversial health care guidelines: Doctors should stop performing a cancer screening they’ve provided for decades.

(Toby Melville/Reuters)

The PSA test produces a high level of false positives, with about 80 percent proving not to be cancer. Studies find it does not save lives, largely because prostate cancer often grows too slowly to ever cause medical harm.

The recommendation was certainly divisive: One in two doctors agree with it, according to a new survey published in the Archives of Internal Medicine. Nearly all doctors, however, agree on one thing: Regardless of the guideline’s validity, they did not plan to follow it in practice.

Only 1.8 percent of primary care doctors said they would no longer provide routine PSA tests. The survey looked at primary care doctors in Maryland affiliated with the Johns Hopkins Community Physicians. Among that group, 49 percent agreed that ending the PSA test made sense, while 36 percent disagreed.

Researchers asked the doctors what seems like the most obvious question here: If you agree with the guidelines, why not follow them? Three-quarters of the doctors said it had to do with their patients, who expected doctors to continue providing the tests. Two-thirds said they didn’t have the time to explain the changes — it was faster just to perform the best — while a quarter worried that patients would think their health care was being rationed.

“The results suggest that...the USPSTF recommendations may encounter significant barriers to adoption,” the researchers conclude. “To the extent that PSA screening should be reduced, it may be necessary to address patient perceptions’ about screening, to allow adequate time for screening discussions, and to reduce concerns regarding malpractice litigation.”

Part of the challenge may have a lot to do with how we think about medicine. Screenings are supposed to lead to early detection, treatment and, eventually, a cure. As my colleague Brian Vastag writes, we don’t hear much in the way to contradict that narrative: “No one says: I got a PSA test. It was high, so I got a biopsy. The biopsy caused pain for weeks and made me bleed. But I didn’t have cancer. Good thing I got that test.”

Beyond the PSA test, the results of this survey also speak to some larger challenges for a growing movement to end unnecessary health care. A few months ago, a group called Choosing Wisely issued a list of 45 procedures that doctors often perform — but don’t think they should, because they provide little to no benefit.

That list was well-received by medical communities, seen as a laudable way to lower health care costs without reducing quality of medicine. It does, however, leave a lingering question of enforcement: How do you make sure that doctors stop performing the procedures they don’t think are necessary? As this study suggests, there’s a whole host of obstacles that stand between identifying a specific procedure as wasteful — and actually reducing its use in our health care system.