Prostate-specific Antigen and Prostate Cancer: How can We Improve Specificity and Predictive Power of the Marker?

Abstract

PSA is commonly used in diagnosing prostate cancer but it lacks both specificity and sensitivity; PSA values rise in benign prostatic affections and up to 30% prostate cancers show normal PSA values. Preliminary reports indicate that PSA DENSITY (PSAD), i.e. PSA/prostate-volume ratio, can improve specificity of PSA in diagnosing prostate cancer. We considered PSAD in 55 patients of 160 observed for prostatism: all of them underwent digital rectal examination, transrectal ultrasound and multiple biopsies of the gland. We found cancer in 19 patients (PSAD ranging from 0.17 to 1.77, with a mean value of 0.45), 26 prostatic hyperplasia (PSAD from 0.003 to 0.75, with a mean of 0.13), 6 dysplasia (PSAD from 0.07 to 0.30, with a mean of 0.19). In our experience PSAD > 0.17 or mean value > 0.45 indicate cancer in the absence of significant digital rectal examination and ultrasound findings or normal and borderline PSA values.