Prostate cancer screening may help healthy men only

NEW YORK (Reuters Health) - Screening men for prostate cancer makes sense only if they are generally healthy, U.S. researchers said on Monday.

They found that even if screening doesn’t help men live longer overall -- as shown by a large U.S. study last year -- it’s possible that some may still benefit.

Today, doctors commonly screen men over 50 for prostate cancer using a prostate-specific antigen (PSA) blood test, which costs $50 or more.

This practice is controversial, however, because prostate tumors are often slow-growing, and screening may result in many men undergoing surgery, radiation or other treatments for cancers that would never have threatened their lives.

So those treatments -- with their risks of side effects like erectile dysfunction and urinary incontinence -- can potentially do more harm than good for many men.

U.S. federal health officials are currently looking into the issue, but so far say the evidence is insufficient to make sweeping recommendations for men younger than age 75. For those more senior, the U.S. Preventive Services Task Force discourages screening.

For the new study, doctors re-analyzed data from an earlier report that found no difference in death rates among more than 70,000 men who had been randomly assigned to annual screening or usual care.

Over ten years, prostate cancer killed about two in 1,000 men. And screening did nothing to help those who had health problems that put them at risk of dying from heart disease or cancer, two major killers in the US.

But it slashed the rate of cancer deaths by nearly half in the 26,000 men who didn’t have such issues. That means 723 men would have to be screened and five would have to be treated to prevent one prostate cancer death at ten years.

“The reason why the original study appeared to be negative is it looked at all patients,” said Dr. Anthony V. D’Amico, an oncologist at Brigham and Women’s Hospital in Boston, who worked on the new analysis.

“What this study suggests is that PSA tests could be used more selectively in men who are in good health,” he told Reuters Health. “For men who aren’t as healthy, it suggests that screening may not make a difference.”

An unhealthy 60-year-old, D’Amico explained, might simply not live long enough to reap the benefits of removing slow-growing tumors.

Dr. Ned Calonge, who heads the U.S. Preventive Services Task Force, cautioned that analyses based on earlier data could often lead to “exaggerated or mistaken conclusions.”

He noted, for instance, that the less-healthy men who were screened appeared to have a higher risk of dying from prostate cancer than those who weren’t -- a finding that is hard to explain.

“This does not trump the results of the original study,” he told Reuters Health by e-mail, “but provides an interesting finding that may prompt additional research on this issue.”

SOURCE: Journal of Clinical Oncology, online November 1, 2010.