Use of the prostate-specific antigen, or PSA, blood test for detecting prostate cancer has been dogged by controversy for years. Today, members of the American Urological Assn.issued their latest interpretation of the value of PSA testing, saying that "well-informed men 40 years of age or older who have a life expectancy of at least 10 years" should be offered the test.
Prostate-specific antigen is a substance made by cells in the prostate gland. The antigen is found in a small amount in the blood, but levels can rise in men with prostate cancer. The risk of prostate cancer is related to a PSA score. A baseline PSA level above the median for men age 40 is considered a strong predictor of prostate cancer and may warrant further tests. Factors such as the patient's age, overall health, family history and ethnicity should also be considered along with the PSA score in assessing cancer risk.
The recommendation, issued at the annual AUA meeting in Linthicum, Md., stands in contrast to recommendations made by other groups. The American Cancer Society does not recommend routine testing for prostate cancer, saying that the test is not 100% accurate, that uncertain test results cause confusion and anxiety, and biopsies to clarify the results carry a small risk and discomfort. According to ACS guidelines, men age 50 and older of average risk for prostate cancer and who have at least 10 years of life expectancy should be offered the PSA test and a digital rectal exam. This discussion should take place at age 45 for men at higher risk, such as African Americans, or at age 40 for men with several first-degree relatives who had prostate cancer at an early age.
The U.S. Preventive Services Task Force updated its screening recommendations last year, saying that the risks of screening outweigh the benefits for men age 75 and older. Men under age 75 should discuss the PSA test with their doctors and personal preference should guide their decision.
Two studies published online last month in the New England Journal of Medicine also cast doubt on the value of prostate cancer screening. The studies found screening does not save lives and can lead to unnecessary treatment. One study in Europe showed screening 1,400 men and treatment of 48 cancer cases were required in order to save one life.
But when offered and interpreted appropriately, the PSA test may provide important information to many men, the AUA said.
"The single most important message of this statement is that prostate cancer testing is an individual decision that patients of any age should make in conjunction with their physicians and urologists," Dr. Peter Carroll, chairman of the panel that developed the recommendations, said in a news release. "There is no single standard that applies to all men, nor should there be at this time."
The issue of when a biopsy should be conducted is also controversial. In the new guidelines, the AUA says the decision to have a biopsy should take into account other factors, including free and total PSA values, PSA velocity and density, the patient's age, family history, ethnicity, previous history of biopsies and general health.
Men and their doctors should discuss the risks involved with the PSA test, such as the possibility of detecting some cancers that may not need immediate treatment.
"Prostate cancer comes in many forms, some aggressive and some not," Carroll said. "But the bottom line about prostate cancer testing is that we cannot counsel patients about next steps for cancer that we do not know exist."
The guidelines are available at www.AUAnet.org.
In February, the AUA and the American Society of Clinical Oncology recommended that men over age 50 who are concerned enough about their cancer risk to get an annual PSA test should consider taking the drug finasteride to lower their risk. The medication is used to shrink an enlarged prostate gland.
-- Shari Roan
Photo credit: Wes Bausmith / Los Angeles Times