RT Journal Article SR Electronic T1 Free / Total Prostate Specific Antigen Ratio for Prostate Cancer Detection: A Prospective Blind Study JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 2439 OP 2443 VO 25 IS 3C A1 CHI-REI YANG A1 CHUNG-KNANG SU A1 KUN-YUAN CHIU A1 HAO-CHUNG HO A1 YEN-CHUAN OU A1 CHENG-LI CHENG A1 HUEI LEE YR 2005 UL http://ar.iiarjournals.org/content/25/3C/2439.abstract AB Background: We conducted this prospective study to evaluate the ability of the percentage of free PSA (% f/t 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.