Deciding whether to get screened for prostate cancer just got trickier. For a while, the tide was clearly turning against routine prostate-specific antigen (PSA) screening.

Now it’s turning back—a little.

For baby boomers only.

Background: Routine prostate cancer screening—looking for the cancer in a healthy man—is very different from PSA testing in a man who has signs or symptoms of prostate cancer. In 2012, the US Preventive Services Task Force (USPSTF) recommended against routine screening—evidence showed that the harms of screening outweighed its benefits.

Study: The USPSTF has updated its findings by evaluating all high-quality medical research on the topic up through October 2016.

Finding: Recent studies show that the benefits and harms of screening are closely balanced for men between the ages of 55 and 69. That’s the core “baby boomer” demographic.

Benefits: For every 1,000 men age 55 to 69 who are screened with a PSA test, one or two will avoid dying from prostate cancer over the next 13 years because of the test. For these men, screening allows early detection so that the cancer can be treated successfully.

Harms: Between 20% and 50% of men age 55 to 69 who are screened and then found to have prostate cancer actually are overdiagnosed—meaning cancer is detected that would never cause any symptoms or endanger their lives. Here’s why: Prostate cancer is usually so slow to grow that these men will end up dying from something else before the prostate cancer has a chance to spread and do damage. For these men, treatment offers no benefit. But it comes with a host of harms, starting with years of additional testing and, if cancer is treated, possible side effects including sexual impotence and urinary incontinence. As the Task Force notes, “Many more men experience harms from prostate cancer screening, diagnosis, and treatment than experience benefit.”

Recommendation: The Task Force doesn’t go so far as to recommend routine screening for all men age 55 to 69. But it does advise that these men talk with their health-care providers about whether to have the PSA test—weighing their health history and personal preferences. Why preferences? Because in the minds of some men, the small chance of living longer outweighs the larger chance of being harmed by over diagnosis—and for other men, vice versa. Given the complexities of the data, there’s no one right answer. This is a substantial change from the earlier recommendation against all PSA testing in healthy men in this age group.

For men older than 69, the Task Force recommends against routine PSA screening. For these men, the harms of overdiagnosis clearly outweigh the benefits of early detection. (Though again, individual men may feel differently.) The Task Force does not have a recommendation for men younger than age 55.

Surprising finding number one: There is no separate screening advice for men already known to be at high risk for prostate cancer due to race or family history. It’s possible that they may benefit more from PSA screening that normal-risk men, but it’s just not known. “The Task Force remains concerned about the striking absence of evidence on the potential benefits and harms of screening and treatment for prostate cancer in high-risk men, particularly African American men, and strongly advocates for research in this area. This should be a national priority.”

Surprising finding number two: One major reason the Task Force changed its recommendation wasn’t improvement in detection—but changes in treatment. The statement makes it clear that active surveillance, when done right, can reduce the harms associated with screening by delaying treatment—and only initiating it if the cancer becomes a more active threat. Active surveillance, which is appropriate for generally healthy men with low-risk disease, involves routine monitoring with PSA tests, office visits and repeat biopsies—rather than immediate surgery, radiation and medications. It’s become much more common in recent years.

Bottom line: The updated guidelines emphasize that the choice of screening belongs—as it always has—to each individual man and that the decision should be made in personal consultation with a doctor. With knowledge and proper management, screening does not necessarily lead to unnecessary exploration and treatment.