Suitability of rapid PSA test for prostate cancer screening in Tanzania

Abstract

Background Prostate cancer is the second leading cause of death in men above 50 years old. Because of late diagnosis, many people turn to hospital when the disease is at an advanced stage, and no longer manageable. Despite the wide uses of prostate specific antigen (PSA) as screening tool in the world, very few Tanzanians have access to this service. The quantitative PSA assay currently used in Tanzania is not widely available because it requires: expensive equipment, skilled personnel and the test itself is costly. However, in other countries, a qualitative assay which is relatively cheap, does not require sophisticated instrument and can be used even in remote areas is available and in use. Therefore in order to detect early prostate cancer, a suitable screening tool is required to be developed and implemented, since the disease is potentially curable when diagnosed early. Aim of the study The aim of this study was to establish the accuracy of qualitative (rapid) PSA test by comparing with quantitative PSA ELISA assay and to determine whether obesity affects the level of PSA among Tanzanian men above 45 years of age. Methodology A total of 185 men above 45 years of age were recruited, blood sample were analyzed at the MUHAS-Microbiology laboratory, by both qualitative PSA method, and quantitative PSA ELISA assay. Participants filled in questionnaires from which the BMI data, smoking status and alcohol consumption behaviors were obtained. Data were analyzed using SPSS version 17. Results Using PSA ELISA as a gold standard, the rapid PSA test showed sensitivity of 95.2%, specificity of 82.4%, PPV and PNV of 55.5% and 82.4% respectively. The BMI correlate with PSA level (r= 0.908) likewise obesity was strongly associated with elevated PSA level, with a relative risk of 1.24. On the other hand, other risk factors (smoking status and alcohol consumption) showed negative association with PSA level. Their relative risks were 0.38 and 0.39 respectively. vi Conclusion Rapid PSA test could be used for mass screening of prostate cancer so as to increase access of the test to most of Tanzanian men. Obesity, smoking and alcohol consumption are risk factors that could interfere with PSA screening.