NEW YORK (Reuters Health) – The rate of early prostate cancers among older Americans dropped suddenly following a change in screening advice from government-backed experts in 2008, new research shows.

The findings are another sign that the tide could be turning against routine prostate cancer screening, which a growing number of medical groups worry could do more harm than good.

In August, 2008, the U.S. Preventive Services Task Force began discouraging screening in men over 75 given the known risks of screening and lack of clear benefits. (The group recently expanded its recommendation to men of all ages.)

A survey published earlier this year found no decrease in screening. But that work was based on screening tests reported by patients and could be unreliable, said David H. Howard, a health policy researcher at Emory University in Atlanta, who did the new study.

Using a national cancer registry known as SEER, he found the rate of early-stage prostate tumor diagnoses among men aged 75 and older fell 25 percent from 2007 to 2009 – from 443 to 330 per 100,000 men.

While more-advanced tumors and those in younger men also were on the decline, the drops were not as drastic or sudden as among older men.

That suggests the revised guidelines had an impact on doctors, although insurers still pay for the prostate-specific antigen, or PSA, blood test used to screen for prostate cancer, Howard told Reuters Health.

“Voluntary compliance is better than nothing,” he said, “but obviously there is still a long way to go. That may include policy and insurance changes.”

According to Howard, about half of elderly men in the U.S. still get screened. Research shows other kinds of cancer screening are also common among seniors, despite doubts about their efficacy in this age group.

More than 2.5 million men in the U.S. are living with a prostate cancer diagnosis today, according to the American Cancer Society, but the vast majority won’t die from the disease. That’s because many of these cases represent tumors that were picked up by PSA tests without ever having caused any symptoms.

Experts say men with early-stage prostate cancer may choose to wait and see if the disease progresses, which it often doesn’t do, instead of getting aggressive treatments such as surgery or radiation right away.

Although it’s unclear if such treatments are any more helpful than the wait-and-see approach, side effects such as impotence or incontinence are common.

So far, it’s impossible to say whether the drop in the number of early diagnoses will be accompanied by changes in prostate cancer death rates. If there is no uptick in deaths, that will be a sign that the PSA test is being overused.

The Archives of Internal Medicine, which published Howard’s results, welcomed the findings in a note entitled “Time to Stop Screening for Prostate Cancer.”

“Given that the harms of screening… outweigh the benefits for younger men as well,” editor Dr. Mitchell Katz wrote, “we hope to see a similar decrease in early prostate cancer incidence in young men.”

SOURCE: bit.ly/KEPNSw Archives of Internal Medicine, online July 23, 2012.