Actual Contribution of Free to Total PSA Ratio in Prostate Diseases Differentiation

To determine significance and sensitivity of the Free to Total prostate specific antigen (PSA) ratio (%fPSA) in diagnosis of prostate cancer and to correlate its sensitivity and specificity with diagnosis.

Research included 220 patients, who had indication for biopsy (Clinic for Urology, University Clinical Center Sarajevo).

Average age of patients was 64.6 ± 8.1 years. Kruskal Wallis test indicates that there is a significant difference in age in relation to the diagnosis (KW χ²=12.508; p=0.006). The correlation between the %fPSA level and diagnosis is positive and statistically significant (r=0.211; p=0.002) in the sense that cancer patients have the lowest %fPSA. Analysis of the sensitivity at 95% specificity of %fPSA compared to particular diagnosis shows the highest sensitivity for prostate cancer - 20.61% (8.35-31.02) with statistically significant AUC p<0.05. Analysis of %fPSA test in detecting prostate cancer, at cut-off values ≤ 0.16, shows a sensitivity of 72.3% and specificity of 50.4 (at cut-off values <0.07, sensitivity is 8.4%, and specificity is 97.8%).

PSA is organ specific but not cancer specific marker, whose total value, as well as the %fPSA serve as a basis, with a digitorectal exam, in the detection of prostate cancer. By increasing the cut-off values sensitivity of %fPSA increases and specificity decreases. %fPSA has a relative importance in the detection of prostate cancer, and should not be used as a guideline, without prior clinical examination.