To assess the correlation between prostate specific antigen density and prostate biopsy results of patients with raised PSA at Kenyatta National Hospital.

Abstract

Background: PSA density is one of the diagnostic tools used to screen for prostate cancer. Several studies have been done to establish the ideal cut-off for PSAD however no consensus has been established due to the different biological differences between different populations. OBJECTIVE: Correlate prostate biopsy results with Prostate specific Antigen Density of patients with raised Prostatic Surface Antigen in Kenyatta National Hospital. METHODOLOGY: The study was a prospective cross-sectional study. It was conducted among patients who presented with PSA >4ng/ml or had abnormal digital rectal examination finding seen at KNH. The study was conducted between May 2019 and August 2019 involved 77 patients with PSA>4ng/ml or suspicious DRE findings. The sample size was met by non-randomized consecutive sampling. They each had PSA value established. Their prostate volume was measured and subsequently a PSA density was calculated. The formula: PSA density = Total PSA/Prostate volume was used. A prostatic core biopsy was then be taken by trans-rectal ultrasound guided method. The results were then compared with the PSA density to determine whether they are in congruity with each other. The inclusion criteria were patients with elevated index PSA or abnormal DRE findings provided they give an informed consent. The exclusion criteria were ongoing UTI, previous prostate surgery, hormonal treatment, use of alpha blockers or 5Alpha Reductase Inhibitors, radiation therapy, and those who will declined to give consent for the study. The data collected was filled in the data collection form after consent was taken from the patient. The collected data was entered into a Microsoft Excel sheet and then a statistical analysis was done using SPSS. The values of the continuous variables were demonstrated as means +/- Standard deviation. Sensitivity and specificity, positive and negative predictive values of various PSADs were determined. Sensitivity was defined as number of true positive results divided by sum of true positives and false negatives. Specificity was defined as number of true negatives divided by sum of true negatives and false positives. Negative predictive value was defined a proportion of negative results that are true negatives. Positive predictive value was defined as the proportion of positive results that were true positive. The results will be demonstrated using tables, pie charts and graphs. RESULTS: 77 patients were recruited into the study. The average age was 69.5years. For the IPSS score, 37 (48.1%) had a moderate score, 30 (39.0%) had severe, while 10 (13.0%) had mild score. PSA levels ranged between 0.78 to 3514 ng/ml with a mean of 94.9 ng/ml and a median of 18 ng/ml. Prostate volumes ranged from 21.0 cc to 464.0cc with a mean value was 89.8 cc while the median value was 73.0cc. PSAD results showed that 50 patients (64.9%) had PSAD values of 0.15 and above, while the 27 (35.1%) had below 0.15. As for biopsy results out of the 77 patients, 41 (53.2%) of the patients had prostate adenocarcinoma, while 30 (39.0%) having benign prostatic hyperplasia alone while the other 6 (7.8%) having a benign prostatic hyperplasia with prostatitis. Using Receiver Operating Characteristic Curves were used to establish a PSAD cutoff and was established as 0.23.xii CONCLUSION: A PSAD of 0.23 can be used as a cut-off value to predict prostate cancer when evaluating patients with raised PSA in our population. Above this value patients should be subject a prostate biopsy.