[Sensitivity and specificity of serum PSA, free to total PSA ratio and transrectal ultrasonography findings in prostate cancer detection]

ABSTRACT

We conducted this study to evaluate and compare the sensitivity and specificity of various para-clinic parameters in detecting prostate cancer. In this cross-sectional study, 220 patients who underwent prostate biopsies for either high serum PSA level or abnormal digital rectal examination. Sensitivity and specificity of serum PSA, free to total PSA ratio and transrectal ultrasonography findings were calculated. Based on the pathological findings in 220 cases, 25% were diagnosed with prostate cancer. The mean age of patients with prostate cancer was 69.11 +/- 8.6 years. Mean serum PSA level among prostate cancer patients was significantly higher than in other patients [19.5 +/- 17.5 ng/dl vs. 10.5 +/- 8.1 ng/dl] [P=0.003]. The sensitivity and specificity of PSA for detecting prostate cancer, considering cut-off value of 4 ng/dl, was 92% and 2%, respectively. Free to total PSA ratio with cut-off value of 10% revealed 82% sensitivity and 17% specificity. Moreover, hypoechoic lesions detected by transrectal ultrasound had a sensitivity and specificity of 34% and 93%, respectively. Combination of different PSA related parameters with tranrectal ultrasound findings might increase sensitivity and specificity in detecting prostate cancer and reduce unnecessary biopsies