A pilot study on percent free prostate specific antigen as an additional tool in prostate cancer screening.

A cross sectional pilot study was carried out to look into the usefulness of percent free prostate specific antigen (fPSA) in the diagnosis of prostatic cancer in HUSM patients. All patients who attended surgical clinic and admitted to surgical wards with signs and symptoms of prostate problems during the study period were taken as the study subjects. Total prostate specific antigen (tPSA) was estimated by immunoassay technique and those values of 4 ng/mL or more were proceeded for estimation of fPSA. Using the cut-off value of less than 25% fPSA for diagnosing patients with prostate cancer, our study showed that majority of the prostate cancer patients have a ratio of fPSA:tPSA more than 25% and a significantly higher level of total prostate specific antigen (P<0.005) when compared with patients with benign prostatic hyperplasia (BPH). Unexpectedly, the fPSA values were high in patients diagnosed as prostate cancer compared to BPH. Ratio of percent fPSA to tPSA was found not to be sensitive and specific, in diagnosing prostate cancer at the cut-off value of 25%. In conclusion, total PSA is a more useful biochemical test for diagnosing prostate cancer in our patients.