PSA Test a Cause for Concern? Not So Fast
A recent study in the Journal of the National Cancer Institute questions whether the PSA test may lead to an overdiagnosis of cancer in some men. Does this spell trouble for the popular test? Not so fast, says William J. Catalona, M.D., professor at Washington University in St. Louis.
"The PSA test is extremely valuable," he says. "The findings show that PSA screening detects a large percentage of tumors that will impact the patient. Since prostate cancer is the second leading cause of cancer death in men, it makes sense to do all we can to detect tumors as early as possible."
The study, conducted by the Fred Hutchinson Cancer Research Center and the National Cancer Institute, used a computer model to determine overdiagnosis rates. The authors defined overdiagnosis as men whose cancer would be detected by PSA screening, but would not otherwise be detected during their lifetime.
Based on their findings, the authors determined that most tumors picked up by PSA testing would have presented clinically eventually. They found that, at most, only 15 percent of the latent tumors in whites and 37 percent in blacks would be detected by PSA screening.
The bottom line: The authors estimated that only 4 percent of whites and 7 percent of blacks would be overdiagnosed for prostate cancer. And the potential adverse consequences of overdiagnosis would be reduced if experienced clinicians identified patients with potentially harmless tumors and did not treat them.
"These findings are consistent with clinical studies that show that PSA screening largely detects tumors that are likely to impact the patient," says Dr. Catalona.
In other words, he says, there is significant value in PSA tests, such as Beckman Coulter's Hybritech® PSA assay. "The PSA test is more effective at helping to detect prostate cancer than a mammogram is at detecting breast cancer," he notes.
Nearly 200,000 men in the United States will be diagnosed this year with prostate cancer, according to the American Cancer Society. The ACS recommends that all men, beginning at age 50 years with at least a 10-year life expectancy, should be offered an annual PSA test and digital rectal examination (DRE). Men at high risk should begin testing even earlier.