The American Cancer Society has been cautious about making blanket recommendations for prostate cancer screening for years; since 1997, the group has said screening with a PSA test should be offered to eligible men but that physicians should explain the uncertainties and potential risks of the test as well as the possible benefits. That basic recommendation hasn't changed in the ACS's latest guidelines for prostate cancer screening, published online today in CA: A Cancer Journal for Clinicians. But the guidelines, updated after two large trials of prostate cancer screening last year reached mixed conclusions about whether it saves lives, cast light on a process you may soon be hearing more about: shared, or informed, decision making.
As it applies to prostate cancer screening, that means men eligible for the prostate-specific antigen test—those 50 and older who are at average risk and younger men who are at higher risk because they have a family history or are African-American—need to know that while screening "may be associated with a reduction in the risk of dying from prostate cancer … evidence is conflicting and experts disagree about the value of screening," the ACS says. (To explore two sides of that debate, read Benefits of PSA Test Are Exaggerated and PSA Cancer Screening, Much Like a Seat Belt, Is a Wise Choice for Men.)
Men also should discuss with their healthcare providers the potential benefits of early screening, the strengths and limitations of the PSA test, and the risks of finding and treating screening-detected cancer—namely, that cancers that never would have been a threat to life or health are treated, with the potential for side effects like impotence, the ACS says. In weighing a decision, the man should consider his own values—for instance, whether finding any degree of cancer early and rooting it out trumps any risk of incontinence. He also needs to decide what level of participation in the decision he is comfortable with. Some men will still want to defer to their physician, says R. Jeffrey Karnes, an assistant professor of urology at the Mayo Clinic in Rochester, Minn. But even so, the idea is that having the discussion will let the doctor decide based on the patient's preferences. The ACS recommends tools, including its own and one from the Foundation for Informed Medical Decision Making, to help doctors guide men through the decisions.
[For more on shared decision making, read Medical Treatment: Patients and Shared Decision Making]
But the gist of all this is a firm end to the notion, still held by some clinicians, that screening for prostate cancer is "the same as colorectal cancer screening or cholesterol screening," says Durado Brooks, director of prostate and colorectal cancers for the ACS and coauthor of the report.
"There has to be a conversation," says John Davis, assistant professor in the department of urology at the M. D. Anderson Cancer Center in Houston. "And these guidelines give some very nice bulleted points and Web links you could build into an information sheet and give to patients."
That's a good message to get across, says Michael Barry, president of the Foundation for Informed Medical Decision Making. "It really feels to me like this guideline is kind of a model for thinking coolly about what the evidence really shows," he says. Men have been screened for years on the assumption that the PSA test saves lives, but that isn't at all clear. And even if you do believe—as does Barry—that there is "a small but finite benefit," there also are potential harms for the men who undergo unnecessary follow-up testing and treatment. (While there is a debate over the risks and benefits of mammography to screen for breast cancer in normal-risk women under 50, Brooks says the situations aren't analogous because there is "much more evidence that screening is beneficial" for breast cancer.)
The ACS didn't change any of the basic guidelines for prostate cancer screening. For men at average risk of the disease, the PSA-or-not-to-PSA discussion should still begin at age 50. It should start at age 45 for African-American men and those with a father or brother diagnosed with the disease before age 65. Men with multiple family members diagnosed before age 65 need to speak with their doctor about screening at age 40. And men who have less than a 10-year life expectancy should not be screened, the ACS says. The society also says that men whose PSA levels are less than 2.5 ng/ml can be screened every other year.