Giving men decision-making tools to help them consider the pros and cons of prostate cancer screening changed how they valued different possible outcomes but did not affect how many chose to be tested, in a new study.

A report last month suggested that one in four family doctors regularly screens men for prostate cancer without asking their permission.

When doctors do discuss screening with patients, using any decision aid could help men make better choices about what's important to them - such as catching extra cancers, possibly reducing their risk of death or avoiding unpleasant side effects - researchers said.

"It's critical to determine how best to help men make these difficult decisions, especially when they're weighing different factors," said Dr. Craig Pollack, who has studied doctors' attitudes toward prostate cancer screening at Johns Hopkins Medicine in Baltimore, Maryland, but wasn't involved in the new research.

Last year, the government-backed U.S. Preventive Services Task Force recommended against prostate specific antigen (PSA) tests for normal-risk men, saying there is no evidence screening has more benefits than harms.

Although it's unclear whether screening saves lives, further tests after a positive screen, such as invasive biopsies, can lead to complications including impotence and incontinence.

Screening is still acceptable, according to the USPSTF, if the man being tested understands the possible outcomes - good and bad - and makes the personal decision to get tested.

"One of the elements of a good decision is that a man's own values are incorporated into the process," said Dr. Michael Pignone, who worked on the new study at the University of North Carolina at Chapel Hill. "In some cases, the evidence isn't so clear that one option is best."

PSA testing is one of those cases, he told Reuters Health.

For the new study, Pignone and his colleagues tested three possible decision aids to help 911 U.S. and Australian men think about the possible benefits and harms of prostate cancer screening.

Those aids had men rank the importance of catching a cancer or not becoming impotent, for example, or asked them to choose - in various formats - their preference for different possible outcomes of screening or not screening.

The decision tools led to some variation in what men considered most important and how they weighed the risk of dying from prostate cancer against possible side effects of testing, the researchers reported Monday in JAMA Internal Medicine.

But after using any of the aids, about three-quarters of men said they planned to get screened.

The one exception, the researchers found, was that men were more likely to choose a no-screening option when the choices weren't marked specifically as PSA versus no PSA.

"The PSA label and the testing label has been something that men have associated with positive characteristics that aren't necessarily true or real," Pignone said.

About one in six men will be diagnosed with prostate cancer during his lifetime, according to the American Cancer Society, and one in 36 will die of the disease.

"I have these conversations with my patients, and they are conversations that can be hard to have, and so having tools that help patients understand the risks and benefits and help clarify their values can be helpful," Pollack told Reuters Health.

"What this study says is, it's not just having a decision aid but also figuring out the best way to help patients clarify their values," he added.

"It's important for men to try to understand the risks and benefits of prostate cancer screening so they can try to make the best decision for their own life."