Diagnostic yield of estimation of serum complexed PSA as a screening tool for prostate cancer patients

ABSTRACT

The present study aimed to evaluate the diagnostic yield of estimation of complexed prostate-specific antigen [cPSA] in random sample of patients with symptoms suggestive of prostate cancer [PC] and had serum PSA of 2.5-20 ng/ml and no previous histologic proof of prostate cancer. All patients underwent full history taking, complete physical examination and prior to prostatic examination or any manipulations, venous blood samples were collected for ELISA estimation PSA serum levels. Then, patients underwent trans-rectal ultrasonography [TRUS] to assess the prostate and the adenoma volume and the peripheral zone [PZ] of the prostate was checked. All patients underwent 10-core TRUS-biopsy taking from the peripheral zone ofthe prostate. The study included 223 male patients fulfilled the inclusion criteria of the study with mean age of 65.7 +/- 8 years. Mean prostatic volume was 60.1 +/- 14.8 cm3 and the mean PZ calculated volume was 41.8 +/- 9.4 cm3. Histopathological examination of core biopsies defined 23 cases with PC [PC group] with a frequency of cancer detection of 10.3% while the other 200 patients were free of PC [Control group]. Mean estimated serum tPSA and cPSA levels were significantly higher in PC group compared to its level estimated in control group, while serum fPSA levels were non-significantly lower in PC group compared to control group. Mean PSA densities [PSAD, PZ PSAD, cPSAD and PZ cPSAD] were significantly higher in PC group compared to control group. There was a positive significant correlation between the presence of PC and age of patients and with levels and densities of tPSA and cPSA. Using ROC curve analysis to define the most specific predictors of presence of PC revealed that cPSA level was highly specific with AUC=0.987 with a significant difference in favor of cPSA level in comparison to tPSA and fPSA. Using regression analysis defined cPSA level PZ cPSAD and PZ PSAD as the significant predictors of PC and ROC curve analysis of the three parameters defined PZ cPSAD and cPSA serum level as the highest specific predictors of PC. It could be concluded that estimation of serum complexed PSA could define cases of PC with high specificity during screening of patients had serum PSA levels ranged between 2.5 and 20 ng/ml and used in combination with determination of PZ cPSAD are highly significant specific predictors of PC