RELATIVE SENSITIVITY AND SPECIFICITY OF SERUM PROSTATE-SPECIFIC ANTIGEN (PSA) LEVEL COMPARED WITH AGE-REFERENCED PSA, PSA DENSITY, AND PSA CHANGE - DATA FROM THE AMERICAN-CANCER-SOCIETY NATIONAL PROSTATE-CANCER DETECTION PROJECT

Background. Different indexes that may enhance the early detection cap ability of prostate specific antigen (PSA) have been proposed. In addi tion to the indexes relating to the normal PSA level, there are data s uggesting the usefulness of the PSA level relative to prostate gland v olume (PSA density), age-referenced PSA level, and PSA change. Little research comparing the sensitivity and specificity of these measures i n the same population has been reported. Methods. All subjects were pa rticipants in the American Cancer Society National Prostate Cancer Det ection Project. Specificity was studied in 2011 men without prostate c ancer, and sensitivity was determined for 171 men with prostate cancer . Results. Prostate specific antigen change showed the highest specifi city (96.4%), and PSA density the lowest (85.3%). The most sensitive i ndex was PSA density, which was positive for 74.7% of the 171 cases of known cancer. A PSA change of more than 0.75 ng/ml per pear was the l east sensitive index (54.8%). Sensitivity and specificity varied in a narrow range. Improved performance in specificity was achieved only wi th the loss of sensitivity. Conclusions. None of the alternative index es commonly used in general early detection practice demonstrated part icular advantage when compared with the normal PSA concentration, defi ned as no more than 4.0 ng/ml.