In recently published clinical guidance(annals.org) on prostate cancer screening, the American College of Physicians (ACP) calls for physicians to discuss "the limited potential benefits and substantial harms of screening for prostate cancer" with patients between the ages of 50 and 69. The guidance also encourages doctors to perform screening only if a patient expresses a clear preference to do so.
Human prostate specific antigen (PSA/KLK3) with bound substrate from complex with antibody. (Source: E.A.S./CC-BY-SA-3.0)
According to the ACP guidance, any decision to screen using the prostate-specific antigen (PSA) test should be based on
- the patient's risk for prostate cancer,
- a discussion of the benefits and harms of screening,
- the patient's general health and life expectancy, and
- patient preferences.
The ACP further recommends that PSA screening not be performed in average-risk men who are younger than 50 or older than 69, as well as in those who have a life expectancy of less than 10-15 years.
It's worth noting that the ACP guidance statement was derived from an appraisal of available guidelines on screening for prostate cancer. The four guidelines selected for review were those developed by the American College of Preventive Medicine, the American Cancer Society, the American Urological Association, and the U.S. Preventive Services Task Force (USPSTF).
- In its new recommendation, the American College of Physicians calls for physicians to discuss "the limited benefits and substantial harms of the prostate-specific antigen (PSA) test" with patients between the ages of 50 and 69 and encourages doctors to perform screening only if the patient expresses a clear preference to do the test.
- The AAFP and U.S. Preventive Services Task Force recommend against performing PSA screening in asymptomatic men, regardless of age.
- Two family physician experts agree that further research could help identify any subset of men who might benefit from PSA screening.
Although the ACP guidance, which was published April 9 in the Annals of Internal Medicine, does not flatly contradict the AAFP and USPSTF recommendations against performing PSA screening in asymptomatic men regardless of age, some differences in emphasis exist.
In its 2012 recommendation statement, the USPSTF acknowledged that PSA screening is commonly used in practice and that some men will continue to request screening and some physicians will continue to offer it.
"The decision to initiate or continue PSA screening should reflect an explicit understanding of the possible benefits and harms and respect patients' preferences. Physicians should not offer or order PSA screening unless they are prepared to engage in shared decision-making that enables an informed choice by patients," say the USPSTF guidelines.
According to USPSTF member Mark Ebell, M.D., of Athens, Ga., "The ACP assessment of the data is very similar to that of the USPSTF: The benefits (of PSA screening) are, at best, small, and the harms are likely to be moderate. "Of course, some men may still choose to be screened, but I hope they only do so after a careful discussion with their family physician so they understand the potential harms."
Gretchen Dickson, M.D., a family physician and assistant professor of family and community medicine at the University of Kansas School of Medicine, Wichita, said it can be difficult -- for both physicians and their patients -- to wade through sometimes conflicting clinical advice.
"If you follow the USPSTF, you would rarely screen anyone, whereas the American Urological Association suggests starting to offer screening to men at age 40," Dickson said. "Not only is that confusing to physicians, but patients may get mixed messages about what the 'right' answer is for them.
"And, as the recommendations change, that further compounds patient confusion."
Dickson said she appreciates the fact that the ACP guidance recognizes that the PSA test offers limited benefits and substantial harms and points out that screening should not occur in men younger than 50 or older than 69 or in those with limited life expectancy.
"In general, I recommend against PSA-based prostate cancer screening for my male patients in line with the recommendations of the USPSTF," she said. "That recommendation usually comes after a long conversation, though, about what we know and don't know about prostate cancer screening. Given the current evidence, screening seems to do more harm than good for most patients."
The problem, Dickson said, surrounds the knowledge gaps that exist relative to prostate cancer screening.
"Many of the studies that are used to formulate the prostate cancer screening guidelines were done predominantly in Caucasian populations, yet African American men have among the highest risk of prostate cancer," she said. "Perhaps our screening recommendations would change if we had more high-quality evidence from studies involving more racially diverse subjects.
"As we learn more about PSA velocity, density, free PSA and other tests, we may find that screening is warranted for specific populations, but, today's best evidence suggests that screening may do more harm than good for most men."
Ebell agreed that more research would almost certainly help clear the fog a bit.
"There is certainly a need for more research in black men," he said. "But the recent PIVOT (Prostate Cancer Intervention Versus Observation Trial) trial that compared early treatment with active surveillance found no difference in the treatment outcomes for black men (30 percent of those studied) compared with other participants."
Of course, said Dickson, even after explaining the risks to her patients, she does have some men who choose to be screened.
"The difference is that ordering a PSA test isn't something that I just tack on to 'routine labs' for my male patients. We talk about the test a lot before we decide that PSA testing is right for them," she said. "It isn't a short visit, but the conversation reassures me that I've given them all the tools to make their decision.
"The ACP statement acknowledges that by the best evidence we have today, it appears the risks outweigh the benefits of PSA testing for most men," she said. "But ultimately, the physician and the patient must have a conversation and decide if (that patient) is a man who doesn't fit into that 'most men' category."