Many Men Getting Unnecessary Prostate Cancer Blood Tests

(Page 2)

In addition, older male doctors were more likely to order inappropriate PSA tests, Kerfoot said. Female doctors fared better. "As female practitioners age, the appropriateness of their screening increases," he said.

Kerfoot believes the new data may help cut down on unnecessary PSA tests. "The goal is to design educational programs that will teach the practitioners how to use PSA screening more consistently in an age-appropriate manner," he said.

The diagnostic value of PSA remains controversial, Kerfoot noted. There are several trials ongoing that over the next 10 years may help to determine whether the current guidelines need to be changed, he said.

One expert agreed that the PSA test is often misunderstood.

"I am not sure that we use PSA correctly," said Dr. Anthony D'Amico, the chief of radiation oncology at Brigham and Women's Hospital, Boston.

PSA level is affected by many other factors besides cancer, including an enlarged prostate or benign prostatic hyperplasia (BPH). This means that PSA results can lead to an overdiagnosis of prostate cancer, D'Amico said. "It can also lead to missing cancer in younger men," he said.

According to D'Amico, changes in PSA levels over time -- rather than a snapshot look from just one test -- are the key to using the screen correctly. He expects guidelines to change this year to reflect this new method. "When you look at change in PSA level, you can easily distinguish benign versus malignant tissue," he said.

For men in their 40s, a steady rise of PSA of more than half-a-point a year is a probable indication of prostate cancer, D'Amico said. In men in their 60s or 70s, a rise of one point or more may be an indication of prostate cancer, he said. "But once BPH starts, PSA readings become less predictive, especially for older men," he added.

One expert believes that PSA should only be used alongside other factors in diagnosing prostate cancer -- regardless of the man's age.

"It isn't fair that a healthy 75 year-old should be denied a PSA exam" based on his life expectancy, said Dr. Ian M. Thompson, from the department of urology at the University of Texas Health Science Center at San Antonio. "Many older men have more than a 10-year life expectancy," he added.