Performance of PSA and of PSA density in the diagnosis of prostate carcinoma

ABSTRACT

Objective: The aim of the study was to investigate the influence of the prostate volume and PSA density on the performance of total PSA to diagnosis of prostate carcinoma. Methods: We analyzed 217 patients(PSA 0-10ng/ml) submitted to transrectal sextant prostate biopsy. Criteria for biopsy indication was PSA >2ng/ml and/or digital rectal exam suspicious of prostate cancer. Results: Fifty five patients had prostate neoplasia (25.3 percent) and 8/55 (25.3 percent) the serum PSA was under 4ng/ml. The sensitivity and specificity of the test were respectively 98.2 percent /16.6 percent at a cut-off point of 2.5ng/ml and 85,4 percent /38.8 percent at cutt-off of 4ng/ml. The corresponding values for prostates >40ml or <40ml were 96.2 percent /8.1 percent and 100 percent /27.7 percent at the cut-off point of 2.5ng/ml, and 92.5 percent /20 percent and 78.5 percent /62.3 percent at a cut-off level of 4ng/ml. For prostates <40ml a PSA cut-off point of 4ng/ml leads to a misdiagnosis in 21.4 percent of the malignant tumors. The median PSAD of benign prostates are different according to prostate volume (.40ml or <40ml). PSAD at cut-off of 0.08 increases the PSAspecificity at both PSA cut-off points. Conclusions: Prostate volume affects the sensitivity and specificity of PSA and the median values of PSAD. PSAD of 0.08 increases the PSA specificity specially at a cut-point of 2.5ng/ml in prostates smaller than 40ml.