Determination of the sensitivity and specificity of serum prostate-specific antigen in the diagnosis of prostrate cancer in Kano, Northwestern Nigeria

Background: Early detection is an essential step in decreasing the mortality and morbidity related to prostate cancer. Serum prostate-specific antigen (PSA) testing is a proven effective tool for early detection of prostate cancer. It has high sensitivity but low specificity and remains an important screening tool. Objectives: This study aims at finding a local reference sensitivity and specificity level of serum PSA in Kano, Northwestern Nigeria. Materials and Methods: A cross-sectional descriptive study of 93 patients who had lower urinary tract symptoms and digital rectal examination (DRE) findings suggestive of cancer of the prostate and/or raised PSA who presented to urology outpatient clinic of Aminu Kano Teaching Hospital, Kano over the period of one year (January to December 2012). All patients had transrectal ultrasound-guided biopsy for histological evaluation. The sensitivity and specificity of PSA were then analysed. Results: A total of 93 patients participated in the study with age range from 50 to 96 years and mean age of 68.086 ± 9.368 years. The sensitivity of PSA was found to be 91.4% but dropped to 47.3 when the reference ranged were considered at 0-4.0 ng/ml and 0-10.0 ng/ml, respectively. Also, the specificity was found to be 22.4% but raised to 77.0% at the other reference range. The diagnostic accuracies for 0-4 and 4.1-10 ng/ml were 48.0% and 59.1%, respectively. Conclusions: PSA testing still has a role to play in the diagnostic pathway and is relatively non-invasive, inexpensive with a high sensitivity. However, it has a low specificity. The reference range in our environment remains the international range of 0-4 ng/ml.