Prostate Cancer in 15% of Men With Normal PSA
Best Test May Be to Follow PSA Levels Over Time, Expert Says
May 26, 2004 -- Fifteen out of every 100 older men with a normal PSA test actually has prostate cancer, a new study shows.
PSA -- prostate-specific antigen -- is a chemical marker given off by cells of the prostate gland. Suspiciously high PSA levels are often an early sign of prostate cancer. A PSA over 4 ng/mL usually means that a man will have to undergo needle biopsy of his prostate.
Men breathe a sigh of relief when their doctor tells them their PSA is normal. But some men with a low PSA do have cancer. Until now, it wasn't clear how many, says researcher Charles A. Coltman Jr., MD, chair of the Southwest Oncology Group in San Antonio.
"Our study emphasizes that there is a range of PSA levels, from 0 to 4, across which a man can have prostate cancer," Coltman tells WebMD. "There is not a clear cut cutoff based on PSA alone which allows you to define individuals who need to be biopsied."
Driving home Coltman's point is a dramatic picture. It shows a high-grade prostate cancer -- from a man whose PSA level was less than 1. The picture and the study it illustrates appear in the May 27 issue of The New England Journal of Medicine.
Individualized Prostate Cancer Screening
Coltman says that men and their doctors can no longer rely on PSA levels alone when deciding whether to have a prostate biopsy.
"The situation now is that the individual man with his individual urologist will have to assess what the person feels are his risk factors," he says. "In consultation with his doctor, the individual man must come to grips with the question of whether or not a biopsy should be done. It will become a more personalized interaction."
Who's at high risk? Men with the following factors have the highest risk of prostate cancer:
Age. A man's risk of prostate cancer increases with age.
Race. "African American men have the highest incidence of prostate cancer and the highest death rate from prostate cancer of any men in the world," Coltman says.
Family history. A man's risk increases if his brother or father has had prostate cancer.
Prostate Cancer With a Normal PSA
In their study, Coltman and colleagues analyzed data from a clinical trial of nearly 10,000 men. After seven years, they had a prostate biopsy whether they had a high PSA or not.
About 3,000 of these men never had a PSA level of more than 4.0. Fifteen percent of these men turned out to have prostate cancer. And 15% of these cancers were life-threatening, high-grade tumors.
The chances of prostate cancer -- and of high-grade cancer -- went up as PSA levels rose. But high-grade cancers were seen in men at all PSA levels.