Predictive Value of Free to Total Prostate-Specific Antigen Ratio for Gleason Score Results Obtained by Transrectal Prostate Biopsy in Patients with Prostate-Specific Antigen Grey Zone.

Background: To evaluate the correlation between prebiopsy free-to-total prostate-specific antigen ratio (f/t PSA) and biopsy Gleason score (GS) results and determine the diagnostic accuracy of f/t PSA ratio for prostate carcinoma in patients with a PSA grey zone.

Methods: Data on 808 patients were retrospectively reviewed. Based on the f/t PSA ratio results, the patients were classified into three groups. Group 1 consisted of 210 patients having an f/t PSA ratio between 0-0.15; Group 2 comprised 327 patients having an f/t PSA ratio between 0.16-0.25; Group 3 included 271 patients having an f/t PSA ratio >0.25. Demographic and clinical data, including detailed pathological results, were analysed. Assessment of diagnostic accuracy was achieved through receiver operating characteristic (ROC) curve evaluation, and the optimal threshold value of the f/t PSA ratio for the prediction of prostate carcinoma was determined, along with its sensitivity and specificity.

Results: An inverse correlation was observed between the f/t PSA ratio and biopsy GS results. In Group 1, 19% of patients were found to have a GS of 6, but this percentage was nearly halved to 10.7% in Group 3. For those with a GS of 7, the proportion dropped considerably from 40% in Group 1 to 6.6% in Group 3. Similarly, the percentage of patients with a GS of 8 decreased from 9.5% in Group 1 to 1.4% in Group 3. ROC curve analysis revealed an area under curve of 0.756 for the f/t PSA with a 95% confidence interval ranging from 0.724 to 0.785. A threshold value of ≤0.16 provided 57.1% sensitivity and 86.4% specificity.

Conclusions: Although the prebiopsy f/t PSA ratio shows promise as an indicator for the prediction of biopsy GS results, its diagnostic accuracy for the detection of prostate carcinoma is inferior to that of PSA density and prostate volume. Nevertheless, additional research with larger patient groups is needed to confirm these results.