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.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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