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 capability of prostate specific antigen (PSA) have been proposed. In addition to the indexes relating to the normal PSA level, there are data suggesting the usefulness of the PSA level relative to prostate gland volume (PSA density), age-referenced PSA level, and PSA change. Little research comparing the sensitivity and specificity of these measures in the same population has been reported.

METHODS

All subjects were participants in the American Cancer Society National Prostate Cancer Detection Project. Specificity was studied in 2011 men without prostate cancer, and sensitivity was determined for 171 men with prostate cancer.

RESULTS

Prostate specific antigen change showed the highest specificity (96.4%), and PSA density the lowest (85.3%). The most sensitive index 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 year was the least sensitive index (54.8%). Sensitivity and specificity varied in a narrow range. Improved performance in specificity was achieved only with the loss of sensitivity.

CONCLUSIONS

None of the alternative indexes commonly used in general early detection practice demonstrated particular advantage when compared with the normal PSA concentration, defined as no more than 4.0 ng/ml.