Role of Prostate Specific Antigen, Digital Rectal Examination and Trans Rectal Ultrasonography in the Diagnosis of Prostate Cancer in Patients with Lower Urinary Tract Symptoms

Abstract

Sunanda De, Ranjit Kumar Das, Sanhita Mukherjee

Objectives: The aim of this study is to compare the roles of prostate-specific antigen (PSA), digital rectal examination (DRE) and transrectal ultrasonography (TRUS) in the detection of prostate cancer among patients presenting with lower urinary tract symptoms (LUTS) and having an International Prostate Symptoms Score (IPSS) of not less than 7. Material and Methods: This study was carried out in I.P.G.M.E.R and S.S.K.M Hospital, Kolkata, West Bengal, India, from March 2011 to March 2012. Sixty patients presenting with LUTS and with an IPSS not less than 7 had been screened for prostate cancer using PSA estimation, DRE and TRUS. Transrectal sextant prostate biopsy was performed in all patients. Results: The PSA estimation revealed 85% sensitivity and 72.5% specificity for the patients with a serum total PSA level >10 ng/ml. The positive predictive value (PPV) was 60.7%. If 4 ng/ml is taken as a lower cutoff value for serum total PSA, the sensitivity increases to 95%, whereas specificity reduces to 46.66% and PPV becomes 50%. DRE alone showed 60% sensitivity, 92.5% specificity and 80% PPV for the diagnosis of carcinoma prostate. TRUS has the highest sensitivity (75%) and highest specificity (85%). However, the PPV was 71.43%. When DRE and serum PSA >10 ng/ml were combined, the sensitivity and specificity were raised to 90% and 70% respectively. The PPV was 60%. This was almost comparable with the combination of DRE, serum PSA >10 ng/ml, and TRUS, which has a 90% sensitivity and 85% specificity. The PPV was 75%. Conclusion: None of the single screening tools had that much efficacy in differentiating carcinoma of prostate from benign prostatic hyperplasia in patients with LUTS. Combining PSA, DRE and TRUS increases sensitivity, specificity and PPV of PC detection