1 Diagnostic Utility of Complexed Prostate-specific Antigen in the Early Detection of Prostate Cancer in Nigerian Men

Abstract : We evaluate the diagnostic utility of complexed prostate-specific antigen (cPSA) in the early biochemical detection of Prostate Cancer among Nigerian men in Calabar. This was a cross sectional descriptive study involving one hundred and twenty (120) male participants, in two groups of sixty, consecutively recruited from the Urology clinic within a one year period following approval from the Health Research Ethics Committee of the University of Calabar Teaching Hospital. The first group of sixty (60) of the patients were clinically and histologically confirmed to have prostate cancer (PCa) and were treatment naive. While the second group of sixty (60) patients also clinically and histologically confirmed to have benign prostatic hyperplasia (BPH) were used as controls. Participants were between 50 and 80 years old. Sera were analyzed for complexed and total PSA using WKEA ELISA kits and read with STAT FAX 2100 micro plate reader. Values of complexed PSA were higher in prostate cancer than in BPH, with median values of 15.8 ng/mL and 0.9 ng/mL, respectively (P = .001). Similarly, median values of total PSA were higher in PCa (19.3 ng/mL) than in BPH (8.4 ng/mL), P = .001. Receiver operating characteristic curve (ROC) analyses showed area under the curve (AUC) for cPSA to be 0.575, with a sensitivity of 56% and specificity of 62.7% at a cutoff of 1.0 ng/mL, while tPSA had AUC of 0.735, sensitivity of 75.7% and specificity of 64.4% at a different and higher cutoff above 10.0 ng/mL. Complexed and total prostate-specific antigen (PSA) though both sensitive and specific for the biochemical prediction of prostate cancer have some variability with Complexed PSA being an early predictor of prostate cancer than total PSA. This is because complexed PSA was able to detect prostate cancer at very low cutoff value (1.0 ng/mL) when compared to tPSA that was able to detect prostate cancer at a higher cutoff value (>10.0 ng/mL) among Nigerian men. Therefore, complexed PSA is a good biomarker for early biochemical prediction of prostate cancer disease in Nigerian African men when total PSA levels are subclinical.

Keyword : Complexed PSA, total PSA, early diagnosis, prostate cancer, Nigerian men.