Preventing Unnecessary Invasive Cancer-Diagnostic Tests: Changing the Cut-off Points

BACKGROUND: To determine a cut-off point of tPSA and PSAD to prevent unnecessary invasive cancer-diagnosing tests in the community. METHODS: This study was performed on 688 consecutive patients referred to our center due to prostatism, suspicious lesions on digital rectal examination and/or elevated serum PSA levels. All patients underwent transrectal ultrasound guided biopsies and obtained PSAD. Serum levels of tPSA and fPSA were measured by chemiluminescence. Comparisons were done using tests of accuracy (AUC-ROC). RESULTS: Prostate cancer was detected in 334 patients, whereas the other 354 patients were suffering from benign prostate diseases. The mean tPSA in case and control groups were 28.32±63.62 ng/ml and 7.14±10.04 ng/ml; the mean f/tPSA ratios were 0.13± 0.21 and 0.26±0.24 in PCa and benign prostate disease groups; the mean PSAD rates were 0.69±2.24, 0.12±0.11, respectively. Statistically significant differences were found (P <0.05). Using ROC curve analysis, it was revealed that AUC was 0.78 for tPSA and 0.80 for f/tPSA. Sensitivity was 71% for the cut-off value of 7.85ng/ml. For f/tPSA ratio, the optimal cut-off value was 0.13 which produced the sensitivity of 81.4% and for PSAD, it was15%. CONCLUSIONS: As this trial is different from the European and American values, we should be more cautious in dealing with the prostate cancer upon the obtained sensitivity and specificity for PCa diagnosis (7.85ng/mL for tPSA, 15% for PSAD and 0.13 for f/tPSA ratio).