The prostate specific antigen level is a marker to help determine if a man has prostate cancer. Researchers conducted a study to determine the prevalence of men with prostate cancer who had a PSA level of four or less.
Data was used from the Prostate Cancer Prevention Trial. Among 9,459 men in the trial, 2,950 men never had a PSA level of more than four or an abnormal rectal examination. For this research, those men had their PSA measured and underwent a prostate biopsy. Researchers say 15 percent of the men were diagnosed with prostate cancer results showed the prevalence of prostate cancer in men with the lowest PSA number was about 7 percent, while 27 percent of men with a value of 3.1 to 4.0 PSA had prostate cancer.
Thus researchers conclude prostate cancer among men with PSA levels below four is not rare, even though that level is thought to be in the normal range.