Screening for prostate cancer: a study on the free and total prostate specific antigen

Background: A variety of biomarkers have been developed to monitor growth of cancerous diseases and to detect them at an early stage. Prostate-specific antigen (PSA) is a valuable prostate cancer biomarker that is now widely used for population screening, diagnosis, and monitoring of patients with prostate cancer. Other factors than prostate cancer can cause elevation of PSA levels therefore, free prostate specific antigen measurements in serum have been proposed in order to improve the specificity of laboratory identification of prostate cancer. Aim: The aim of our study was to evaluate the diagnostic significance of both total PSA and Free PSA in discriminating prostate cancer from other prostate diseases. Materials and methods: Our study group consisted of 1201 males admitted at outpatient clinic aged between 35 and 84 years old (mean age 63 years). All laboratory measurements were performed on serum samples. The data were statistically analyzed by using descriptive statistics for Windows. Results: The mean total PSA concentration evaluated among 1038 patients was 16.17 ng/mL whereas only Free PSA concentration was evaluated in 163 serum samples and resulted in a mean value of 2.67 ng/ml. In order to calculate the correlation between total and free PSA, data among 69 /1038 patients were further analyzed through statistical program software package for data analysis. Conclusions: Measuring serum free PSA concentrations along with PSA concentrations may provide higher accuracy for detecting prostate cancer and might eliminate unnecessary biopsies in the men with PSA of more than 4.0 ng/mL