Study urges earlier prostate exams

The dubious rite of passage when a man turns 50 might arrive even earlier, based on a study that suggests screening for prostate cancer should begin at 40.

Men are advised to get a yearly screening based on the amount of the prostate hormone PSA found in their blood. A high level is a warning sign of prostate cancer.

Now, a team of Johns Hopkins researchers says screening should begin about age 40 but be done less frequently. The team also recommends basing a diagnosis on multiple readings over time that would show how a man's PSA level changes.

Those changes, the researchers say, would reduce the number of men treated unnecessarily and would better identify potentially deadly tumors that require aggressive treatment.

Their findings, published Wednesday in the Journal of the National Cancer Institute, were based on their study of nearly 1,000 men who volunteered for a long-term study of aging that began in 1958.

Using frozen blood samples, the Hopkins researchers explored whether the speed at which a man's PSA levels changed was a good predictor of his chances of dying of prostate cancer.

Current PSA tests, the researchers said, look at the concentration of the hormone in a man's blood at one point. If the man has a high PSA level, the next step is a biopsy to determine whether he has a cancerous prostate tumor.

Researchers found that the faster a man's PSA level increased, the more likely he was to die of prostate cancer, said Dr. H. Ballentine Carter, a professor of urology and oncology at the Johns Hopkins University School of Medicine and the study's lead author.

''We don't need to diagnose more prostate cancer,'' he said. ''We need to find the prostate cancers that are fatal.''

The current method of looking at a single reading of a man's PSA level proved less effective.

In many cases, Carter said, a man's PSA level increased rapidly before it reached a concentration so high that it would prompt a doctor to order a biopsy. The PSA rise in men who eventually died of prostate cancer sometimes began before age 50. Using the rate of increase -- a measure called PSA velocity -- would have provided an earlier alert, he said.

Carter said that method also would reduce the number of men who undergo treatment for tumors that diminish neither their quality of life nor length of life.

Dr. Mark S. Litwin, who had not seen the Hopkins study, questioned the wisdom of PSA testing for men younger than 50.

Prostate cancer cases are rare in men in their 40s, said Litwin, a professor of urology and oncology at the University of California-Los Angeles. He argued that earlier testing should be reserved for high-risk patients, such as blacks and people with family histories of prostate cancer.

He did agree that looking at the speed at which a man's PSA level changed is a good tool.

''It sounds like it's certainly consistent with prior research,'' he said of the Hopkins study.

This year, the American Cancer Society estimates, more than 234,000 American men will be diagnosed with prostate cancer and 27,000 will die from it.