The value of percentage free prostate specific antigen (PSA) in the detection of prostate cancer among patients with intermediate levels of total PSA (4.0–10.0 ng/mL) in Nigeria
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Date
2012-07-12
Authors
Ezenwa, E.V.
Tijani, K.H.
Jeje, E.A.
Soriyan, O.O.
Ogunjimi, M.A.
Ojewola, R.W.
Ajie, O.I.
El-Nahas, A.R.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Abstract Objectives: To assess the value of percentage free prostate-specific antigen (%fPSA) in the detection of prostate cancer among Nigerian men with an intermediate total PSA level (4–10 ng/mL), and to show if the optimum threshold for biopsy is different from Caucasian values when the widely used (six-core, digitally directed) prostate biopsy protocol in Nigerians is applied.
Patients and methods: The study included 105 patients aged >50 years, with a palpably benign prostate gland and intermediate levels of total PSA (4–10 ng/mL). These patients had a free PSA assay and a transrectal digitally directed six-core biopsy of the prostate. The %fPSA was calculated and the optimum threshold value for detecting prostate cancer was determined.
Results: The mean (SD) age of the patients was 64.4 (6.6) years and their mean (SD) total PSA level was 6.6 (1.7) ng/mL. Of these men 14 (13.3%) had cancer of the prostate detected by the prostate biopsy. The %fPSA level related directly to sensitivity values but inversely to the specificity and the positive predictive values. The best threshold of %fPSA for detecting cancer in these men was <40%, with a sensitivity of 100%, specificity of 93.4% and a positive predictive value of 70% (P<0.05).
Conclusions: In evaluating Nigerian patients with a palpably benign prostate gland and within the intermediate total PSA range, when digitally directed biopsy protocol is adopted, a %fPSA threshold of <40% will detect significant percentage of those with prostate cancer, with a minimal number of unnecessary biopsies. This value differs from that reported in western studies in which transrectal ultrasonography- directed biopsy was used.
Description
Staff publications
Keywords
Free PSA , Intermediate PSA range , Nigeria , Prostate cancer , Research Subject Categories::MEDICINE::Surgery
Citation
Ezenwa E.V., Tijani K.H., Jeje E.A., Soriyan O.O., Ogunjimi M.A., Ojewola R.W., Ajie O.I., El-Nahas A.R.The value of percentage free prostate specific antigen (PSA) in the detection of prostate cancer among patients with intermediate levels of total PSA (4.0-10.0 ng/mL) in Nigeria. Arab J Urol. 2012 Dec;10(4):394-400.