Role of Multiparametric MRI Prostate as A Screening Tool for Cancer Detection

Diagnostic screening for prostate cancer includes digital rectal examination and serum PSA. However several studies have shown that screening using serum PSA and digital rectal examination, did not significantly decrease prostate cancer-specific mortality. The advent of MR in prostate imaging has changes this and the ESUR published prostate MR guidelines in 2012 and also the PIRADS reporting system. Our study aims to assess the ability of mp-MRI to serve as a screening tool for detection of prostate cancer, to evaluate the ESUR PIRADS scoring system for prostate cancer detection using multiparametric MRI, to find a threshold PI-RADS sum (PIRADS-S) score for detection of prostate cancer and to evaluate the usefulness of mp-MRI in patients with serum PSA of 10 ng/mL in diagnosing prostate cancer. From the 54 subjects included, a total of 274 sectors were taken for analysis. All patients underwent mpMRI which included T2,DWI and dynamic contrast enhanced imaging. Using ESUR guidelines individual PI-RADS scores (T2WI, DWI and DCEI) were assigned for all sectors of prostate, following which PI-RADS sum (PIRADS-S = T2WI+DWI+DCEI) score was calculated for each sector. TRUS guided modified sextant biopsy of prostate was done for all patients and correlated with imaging. Statistical analysis was done using independent samples t test and ROC analysis. Sensitivity, specificity, predictive values and likelihood ratios were calculated at various cut-off levels. Optimal cut-off point was calculated by using Youden's statistics. From this study, ESUR PIRADS scoring system showed good diagnostic performance for detection of prostate cancer by using mpMRI and DWI showed the best diagnostic performance. The ROC analysis of PIRADS-S score revealed area AUC of 0.933 with p value of < 0.001. The reported AUC of PIRADS-S score in detecting carcinoma prostate was 0.768 to 0.93. The diagnostic performance of mpMRI was analysed in a group of subjects with serum PSA of 10 ng/mL. mpMRI showed high negative predictive value which indicates the ability of the test to predict the absence of disease with high confidence, thereby helping to avoid a prostate biopsy.