Abstract:

Background: Despite the fact that digital rectal examination (DRE) and serum prostate specific antigen (PSA) has been used worldwide for quite a long time as diagnostic tools in detection of prostate cancer, however their diagnostic utility has not been evaluated at BMC. This existing knowledge gap prompted the author to conduct this study to determine the utility of DRE and serum PSA in the detection of prostate cancer among patients with LUTS at BMC.

Methods and Patients: This was a cross sectional study that was conducted at BMC between January 2019 and June 2019. The study population included all men aged ≥ 50 years presenting to urology clinic with LUTS and enlarged prostate of >30g after detailed history and thorough physical examination, PSA and DRE were performed in series and core biopsy was taken to determine the utility of DRE and PSA in the diagnosis of prostate cancer. The level of significance was considered as p< 0.05. The Kappa statistic (қ) was calculated to determine the degree of agreement with gold standard test (Trucut needle biopsy results). The statistical data analysis was performed using STATA version 13.0.

Results: A total of 199 patients were studied. The median age at diagnosis was 69 years. Prostate cancer was detected in 67(33.7%) patients. The diagnostic accuracy of DRE was 83.9% with sensitivity, specificity, Positive predictive value (PPV) and Negative predictive value (NPV) of 70.1%, 90.1%, 79.7% and 85.7% respectively. The diagnostic error was 16.1%. There was almost perfect agreement with histopathology (κ = 0.89). The sensitivity, specificity, PPV, NPV and accuracy of PSA in the detection of prostate cancer was 98.5%, 54.5%, 52.4%, 98.6% and 69.3% respectively. The diagnostic error was 30.7%. There was a substantial agreement with histopathology (k =0.80). Combining Digital rectal examination (DRE) and prostate specific antigen (PSA), the diagnostic accuracy was 99.5% with Sensitivity, Specificity, PPV and NPV of 100.0%, 99.2%, 98.5% and 100.0% respectively. Error was 0.5%. There was almost perfect agreement with histology (k= 0.95). In patients with abnormal DRE findings, there was a significant association between abnormal DRE findings and high Gleason score (≥7) (p = 0.001). There was almost perfect agreement with Gleason score (k = 0.85). There was no statistically significant association between PSA (≥ 4ng/ml) and increased Gleason score (≥ 7) (p = 605). ). However, there was a substantial agreement with Gleason score (k = 0.76).

Conclusion: This study has highlighted the significant role of DRE and in the diagnosis of prostate cancer and if combined with PSA; there is higher detection rate for prostate cancer than either alone. Therefore, combining DRE and PSA should be used as a complementary diagnostic methods and TRUS be considered optional in the primary evaluation of men with LUT.