#7-S the efficacy of the digital rectal examination, total prostate specific antigen, and prostate specific antigen ratio algorithm in diagnosing prostate cancer

PURPOSE: The primary objective of this study was to determine the efficacy of the algorithm Digital Rectal Examination (DRE), Prostate Specific Antigen (PSA), and free/total Prostate Specific Antigen ratio (PSAr) in diagnosing prostate cancer. A criterion of 1 test, 2 tests and all 3 tests being positive was utilized for the DRE/PSA/PSAr algorithm. METHODS: A sample of 446 males suspected for prostate cancer was referred for transrectal ultrasound and biopsy. All patients consented to participate by allowing venipuncture and DRE prior to sextant biopsy examination. Analysis of PSA and PSAr were performed using Abbott Diagnostics kits. Statistical analysis in determining diagnostic utility for DRE/PSA/PSAr included ROC curve analysis, calculated sensitivity (Sens), specificity (Spec), and likelihood ratio (LR) with corresponding 95% confidence intervals (CI) as well as Kappa statistics. RESULTS: Positivity criteria for PSA and PSAr were identified at >4 and <0.15, respectively. The algorithm of DRE/PSA/PSAr ([Sens = 99%; CI, 1%] [Spec = 3%; CI, 2%], {LR = 1.02; CI, 0.05} demonstrated no significant Kappa agreement (p > 0.05) with the confirmed diagnosis for prostate cancer. The algorithm of DRE/PSA/PSAr with a criterion of one test being positive ([Sens = 99%; CI, 1%] [Spec = 3%; CI, 2%], [LR = 1.02; CI, 0.05] demonstrated no significant Kappa agreement (p > 0.05) with the confirmed diagnosis for prostate cancer. Furthermore, DRE/PSA/PSAr with a criterion of two tests being positive ([Sens = 83%; CI, 5%], [Spec = 61%; CI, 6%], [LR = 2.13; CI, 0.07]) indicated significant Kappa agreement (p < 0.0001). CONCLUSIONS: This study concluded that the algorithm of DRE/PSA/PSAr, with a criterion of one test being positive, failed to enhance specificity compared to the traditional algorithm of DRE/PSA. Furthermore, the algorithm DRE/PSA/PSAr with a criterion of two tests being positive did enhance specificity but sacrificed sensitivity.