(HealthDay News) -- Too many American men are receiving inappropriate PSA (prostate-specific antigen) blood tests for prostate cancer, researchers say.
In many cases, these screenings are being done in populations of either young or elderly men where the test has not proven beneficial, the experts report in the July 9 issue of the Archives of Internal Medicine.
"PSA screening is performed inappropriately in a great proportion in many cases," said lead author Dr. B. Price Kerfoot, from the Veterans Affairs Boston Healthcare System and Harvard Medical School.
For example, most current guidelines do not recommend PSA screening for men younger than 40 years of age, older than 75, or for men who are expected to live less than another 10 years, Kerfoot said. But many men in these groups are nonetheless getting the tests, the study found.
The American Cancer Society notes that, outside of skin cancer, prostate cancer is the most common form of cancer diagnosed among American men. This year nearly 220,000 new cases of the disease are expected to be diagnosed, and about 27,000 men will die of the disease.
The organization currently recommends that men at high risk for prostate cancer, which includes blacks and men with a family or personal history of the disease, should begin undergoing yearly digital rectal exams and PSA blood tests between the ages of 40 and 45.
Otherwise, men with average risk should begin screening at age 50, the society suggests.
In the study, Kerfoot's team collected data on almost 106,000 men treated at Veterans Health Affairs facilities across New England from 1997 to 2004.
Of the more than 232,000 PSA tests given, 16.1 percent were found to be unnecessary, the researchers found. Among this group, 15.3 percent were given to men older than 75, and 0.8 percent were given to patients younger than 40.
Profiling the doctors who ordered these tests, the team found that 51.3 percent were men, 79.4 percent were general practitioners, 53.4 percent were trainee physicians and 8.2 percent were urologists.
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.
Thompson believes that PSA testing should be a part of a total patient evaluation that includes age, a family history of prostate cancer, and whether or not the patient has had a previous biopsy for prostate cancer.
"Men need to read up on the advantages and disadvantages of PSA screening," Thompson said. "Guidelines are only guidelines," he said. Thompson noted that half the men who die from prostate cancer are in their 80s.
"To just say that after 75 you can't have a PSA test doesn't fit with what we know about the biology of the disease, the frequency of the disease, and the risk of the disease," Thompson said.
More information
For more information on the risk for prostate cancer, visit the U.S. National Cancer Institute.
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