The Sensitivity and Specificity of Total Prostate Specific Antigen in the Diagnosis of Prostate Cancer in a Resource-Limited African Setting: A 5-Year Review in a Kenyan Hospital

Introduction

Prostate cancer (CaP) is the most common cancer in males. With rising life expectancy, CaP incidence is increasing. There is a drift from the use of total prostate specific antigen (tPSA) to other PSA parameters for screening. However, theseparameters are not readily available in resource-limited settings.

Objective

To evaluate the sensitivity and specificity of tPSA to make the diagnosis of CaP in an African population.

Methodology

This was a 5-year retrospective review at the AIC Kijabe hospital between January 2018 to December 2022. We included all records of patients treated for prostate disease who had a prostate biopsy and excluded records of patients who had been on a 5-alpha reductase inhibitor or alphablocker and those with urinary tract infection. We used tPSA cut-offs of 4, 10, 20 and 100 ng/ml to calculate sensitivity and specificity.

Results

We included 710 records, of which CaP was the histopathological diagnosis in 327 (46.1%). The mean tPSA was 69.70 ± 2.9 ng/mL. Serum tPSA sensitivity and NPV to diagnose CaP dropped from 99.4% and 96.6% respectively at tPSA ≥ 4 to 59.3% and 72.7% respectively at a tPSA ≥ 100. The specificity and PPV rose from 14.9% and 49.9% respectively at tPSA ≥ 4 to 92.4% and 87.0% at tPSA ≥ 100.

Conclusion

In resource-limited settings, tPSA is still a good screening tool for CaP, with cost-effective PSA cut-off ≥ 10 ng/mL for further investigations. PSA ≥ 100 ng/ml is almost always CaP until proven otherwise.