But about 9 percent have borderline results and may undergo unnecessary biopsies. A large, multicenter study led by a researcher at Washington University School of Medicine in St. Louis suggests that a new version of the screening test clarifies the prostate cancer risk of these men and provides a single cutoff value that can detect 95 percent of prostate cancers. The results were published today in the Journal of the American Medical Association. Lead author William J. Catalona, M.D., professor of surgery and director of the Division of Urologic Surgery, was first to establish the standard PSA test as a screening tool. He says the findings in the clinical trial of 773 men should reduce needless biopsies by 20 percent.
Prostate cancer is the most commonly diagnosed cancer in American men and the second deadliest.
In 1998, an estimated 184,500 American men will learn they have prostate cancer and more than 39,200 American men likely will die from the disease. Levels of this protein can be elevated in prostate cancer. The new PSA test, combined with results from the traditional test, can help distinguish between prostate cancer and other factors that raise PSA levels, such as a noncancerous condition called benign prostatic hyperplasia. It measures a free-floating form of PSA whose levels in blood are significantly lower in men with prostate cancer than in men with the benign condition. Doctors conducted the new PSA test on these men to determine what proportion of their PSA was floating freely.