Background: We conducted this prospective study to evaluate the ability of the percentage of free PSA (% fit PSA) to improve the specificity of prostate cancer (PC) detection.
Materials and methods: Seven hundred and eighty-five patients with serum PSA levels between 4 and 25 ng/ml underwent sextant biopsies of the prostate. The % f/t PSA was analyzed for the sensitivity, specificity and positive predictive values.
Results: The mean % f/t PSA of the 169 patients with PC was 18.0 +/- 7.7 and was significantly (p < 0.0001) lower than that of the 616 patients who had histologically benign biopsy specimens, with a mean % f/t PSA of 26.6 +/- 9.7. Using 30% f/t PSA as the cut-off eliminated 34.4 % of the negative biopsies while still detecting 93.4% of the carcinomas.
Conclusion: The optimal cut-off value of 30% f/t PSA may be applied as reference using the Cis bio international assay for PC detection.