Older men should talk to their doctors about the pros and cons of prostate cancer screening and make an individual decision that is right for them, an influential national panel of experts has proposed.

The new recommendation, based on new data from a European trial as well as changes in the way men with prostate cancer are treated, modifies an earlier panel guideline from 2012 that advised men to skip prostate cancer screenings altogether. Screening is typically done using a blood test that measures levels of a protein released by the prostate gland called prostate-specific antigen, or PSA, which may indicate the presence of prostate cancer when elevated. But increased levels can also be caused by less serious medical conditions, like inflammation.

The panel, the United States Preventive Services Task Force, continues to recommend that men 70 and older forgo screening altogether. But for men 55 to 69, the panel now says, the trade-offs between the potential benefits and harms of screening are too close to call.

“This is a major change in the panel’s position, and it’s a big deal,” said Dr. David F. Penson, a professor and chairman of urologic surgery at Vanderbilt University School of Medicine in Nashville, who was not involved in the developing the new proposal. Even though the panel’s recommendation is a “qualified” one and has yet to be formally adopted, Dr. Penson said, “We’re going to see a lot more men making the decision to be screened.”

The screening recommendations potentially apply to tens of millions of older American men. PSA testing may be followed up with a biopsy of the prostate, which can detect cancer but also lead to complications like pain, bleeding or infection.

Other medical groups are mixed on their recommendations. The American Urological Association recommends shared decision-making between physicians and patients aged 55 to 69, while the American Academy of Family Physicians advises against routine prostate cancer screening. The American Cancer Society recommends starting the conversation between doctor and patient at age 50, and even younger if someone is high risk.

Though screening may have been overutilized in the past, Dr. Penson said, screening rates dropped significantly after the panel’s 2012 recommendation, largely because “men weren’t even being told about it. Doctors didn’t bother saying anything to patients because there was a recommendation against it.”

Prostate cancer is one of the most common cancers affecting men. But while it can be aggressive and fatal in some, many men with an indolent form of the disease never experience symptoms and would not even know they had it if not for screening.

The change in recommendations was brought about by several developments, including additional follow-up data from a European trial that found a slightly smaller number of deaths as well as fewer cases of cancer spreading among men who were screened, compared with those receiving the usual care, said Dr. Alex Krist, a member of the task force and an associate professor of family medicine and population health at Virginia Commonwealth University.

The new results suggest that of every 1,000 men offered PSA screening, 240 will receive a positive result that may indicate prostate cancer and be referred for a biopsy. Only 100 will get a positive biopsy result showing cancer; others who have false positives may still suffer side effects or harm from the biopsy.

Of the 100 found to have cancer, 80 will have treatment like surgery and radiation, and 60 will experience complications, even though up to half of those men will have a cancer that never grows, spreads or becomes life-threatening. But over the course of 10 to 15 years, three cancers will be prevented from spreading, and one to two deaths of prostate cancer will be prevented.

More men who are given diagnoses of low-grade prostate cancer are now undergoing active surveillance, in which they are closely monitored rather than treated with surgery and radiation, and that also played a role in the panel’s decision, Dr. Krist said. “Active surveillance is a way we can reduce some of the harms like overtreatment, and the side effects of overtreatment,” he said.

Individual decisions about whether to undergo screening may be influenced by fear of cancer, prior experiences with the medical system or having friends or relatives who were given prostate cancer diagnoses or experienced side effects from treatment. “Men who have more urgent medical issues might see screening as a lower priority,” Dr. Krist added.

The draft recommendation statement and the panel’s evidence reviews are posted for public comment on the task force’s cancer website — screeningforprostatecancer.org — and will be open to public comment through May 8.

While some advocates for men with prostate cancer were pleased by the proposed change, they said they were concerned that the recommendation would sow confusion and called for more specific guidelines to help patients make decisions, particularly for those at high risk, including African-Americans and those with a family history or symptoms of the disease.

There were also critics. Dr. Kenneth Lin, an associate professor of family medicine at Georgetown University Medical Center and a member of an American Academy of Family Physicians committee that will review the task force’s recommendation, said the panel gave more weight to the results of a European trial that found benefits than to an American trial that did not find such benefit.

And, he said, a lengthy debate of a screening test’s pros and cons would take away from other discussions at a doctor’s visit that may be more productive. “I don’t feel there is enough evidence to shift the balance in favor of more benefits than harms,” he said, adding that it is hard “to assess who’s going to benefit.”