Assessment of serum level of prostate-specific antigen adjusted for the transition zone volume in early detection of prostate cancer

Abstract

Objective: To determine the clinical usefulness of prostate-specific antigen (PSA) density in the transition zone (PSADTZ) for increasing the specificity in early detection of prostate cancer (PCa) and reducing unnecessary biopsies in males with PSA between 4.0 and 10 ng/mL. Materials and Methods: This cross-sectional study obtained PSADTZ measurements in 68 patients with PSA between 4.0 and 10 ng/mL. All patients underwent transrectal ultrasonography (TRUS) with biopsies. PSADTZ was estimated by dividing the PSA value by the volume of the transition zone (TZ) obtained. We compared performance measurements for these parameters with those from the PSA itself, PSA density (PSAD) and free PSA/total PSA ratio (F/T PSA). The ability of the method in increasing PSA specificity was demonstrated and compared in univariate and multivariate analyses, and by Receiver Operating Characteristic Curves (ROC).Results: Of the 68 patients under study, 17 (25%) were diagnosed with PCa. The TZ volume (p = 0.001) and PSADTZ (p = 0.001) variables presented means that exhibited statistically significant differences. When compared with the area under the curve (AUC), ROC curves obtained by this method revealed that PSADTZ was the strongest predictor for PCa when considering the cut-off point provided by the curve; that is, 0.35 ng/mL/cc. When PSADTZ was employed, the detection failure would be close to 20%, and less than 45% of cases would undergo unnecessary biopsies. On the other hand, when F/T PSA was used, the loss would reach almost 40%; however less than 30% would undergo unnecessary biopsies. Nevertheless, PSADTZ had the only AUC presenting p < 0.05 in significance when compared with 50%, and was consequently discriminative.Conclusions: PSADTZ increased PSA specificity in early detection of PCa in males with PSA between 4.0 and 10 ng/mL. However, it was shown to have lower predictive value and lower accuracy than the percentage of free PSA since it presents a higher negative predictive value than all other parameters assessed, and it can be considered clinically useful for reducing unnecessary indications for biopsy.

Comparison between PSA density, free PSA percentage and PSA density in the transition zone in the detection of prostate cancer in patients with serum PSA between 4 and 10 ng/ml

“…As in the article of Djavan et al (13) in this study, in the multivariate analysis the PSADTZ and the %FPSA, were the two variables most strongly predictors of PCa, being that the PSADTZ was the variable that presented the largest predicting power, concurring with the result of the others (2,4,6,7,13,16,19).…”

“…Kikuchi et al (16) found a superiority of the concept of PSADTZ in relation to %FPSA, however the PSADTZ was not better than the PSAD. On the other hand, Ferreira and collaborators (19) found a superiority of the PSADTZ in relation to the PSAD, however the PSADTZ was not better than the %FPSA.…”

“…The literature re-garding the relation between alterations of the PSA serum concentration and the presence of atrophy and/ or prostate inflammation is very limited and controversial (10)(11)(12), thus, the concern in analyzing if the patients with focuses of chronic prostatitis or atrophy were distinct from the patients without such alterations, and it was also a differential of this study as Table-1 makes it evident. Among articles recently published about the detection of PCa, few (6,8,(13)(14)(15)(16)(17)(18)(19) are the ones that analyze and compare, through the ROC curve, the accuracies of the PSA, PSAD, %FPSA and PSADTZ, at the same time, in the range of PSA between 4 and 10 ng/mL.…”