The Role of Prostate Specific Antigen Levels and Prostate Specific Antigen Density in Patients with Lower Urinary Tract Symptoms Aged Over Forty Five Years – A One Year Hospital Based Pilot Study

Abstract

Background and objectives ABSTRACT Widespread screening tests for prostate cancer ( PCa ) based on serum Prostate specific antigen ( PSA ) are undertaken in the western world where a majority of cases are detected at stage T1c. The concept of prostate specific antigen density ( PSAD ) is based on the fact that non-malignant prostatic tissue leaks some PSA into the blood. The objectives of this study was to determine the sensitivity and specificity of PSA and PSA density to detect PCa in patients aged over 45 years presenting with lower urinary tract symptoms. Methods This study was conducted at a tertiary research centre for a period of one year from October 2007 to September 2008. It was designed as a pilot study, which had 50 males over 45 years of age. Patients who had undergone any genitourinary intervention, those who had a previously detected lower urinary tract malignancy or infection were excluded from the study. A questionnaire was supplied which ascertained the International prostate symptom score ( IPSS ) , followed by a clinical examination which included a digital rectal examination ( DRE ) . Serum PSA levels were determined following which Transrectal ultrasound ( TRUS ) was performed to ascertain the volume ( for PSAD calculation) of the gland and to obtain a biopsy. Results The majority of the patients ( 72% ) had a PSA in the traditional grey area between 4 and 10 ng/ml. For a PSAD below the threshold of 0.3 ng/ml/cc no cases of PCa were encountered in our study. Most patients presented to the clinic IX when their symptoms were moderately severe ( 48% ) . The sensitivity ( 88.9% vs. 100% ) , specificity ( 14.6% vs. 95% ) , positive predictive value ( 18.6% vs. 81.2% ) , negative predictive value ( 85.2% vs. 100% ) for PSAD ( at 0.3ng/ml/cc ) was superior to PSA. Conclusion The use of PSAD increases the accuracy and improves the sensitivity and specificity for detection of cancer. In this study the PSA density of 0.3 ng/ml/cc was found to be highly specific and sensitive for detection of prostate cancer.