Discussion
PATHOLOGY
In this study, we evaluated 3 scoring systems based on bpMRI for the detection of csPCa. Our findings demonstrated that all three scorings exhibited high diagnostic performance, and the sensitivity and specificity for Scoring 1 were 64.7% and 80.5%, for Scoring 2 were 86.8% and 73.2%, and for Scoring 3 were 61.8% and 80.5%, respectively. Notably, with Scoring 1 significantly more csPCa were identified as compared with Scoring 2 (P < 0.001) and Scoring 3 (P = 0.03); however, the specificity was decreased substantially (P < 0.001). In light of limited performance that merely depends on scoring systems, we constructed integrated nomograms combining clinical variables of age, PSAD, and scorings to identify csPCa lesions.Our analysis revealed that all 3 models were substantially outperformed using scoring systems alone; moreover, we noted that Model 2 (AUC 0.90) was significantly superior to Model 1 (AUC 0.88, P = 0.04) and Model 2 (AUC 0.88, P = 0.02). To validate these three nomograms, we analyzed 107 patients (36 pathologically proved csPCa) in the validation group. The results showed that the diagnostic performance was consistent with results from the training group, and the AUC for the three models were 0.88, 0.90, and 0.88, respectively. Furthermore, Model 2 was significantly superior to Model 1 while compared using the AUC (P = 0.04); however, the difference was not statistically significant as compared with Model 3 (P = 0.05). Previous studies had reported that combining PI-RADS and other clinical variables or biomarkers was beneficial for improving the diagnostic performance for the detection of PCa; however, most of the nomograms or models from these studies were based on mpMRI and have not been validated in another cohort set [Given the inconvenience and limitation of mpMRI, several preliminary studies have investigated bpMRI that omit the DCE sequence, as which is not need intravenous contrast media and is faster (up to 15 min) [One problem that deserves attention is that no widely accepted standard for how bpMRI addresses the omission of DCE. Some studies proposed that replace the DCE sequence with T2WI [Our study has some limitations. First, this was a single-center retrospective study and patient selection bias may limit the generalizability of our study, thus the results and conclusions need validation in prospective multi-center studies with a larger number of patients. Second, we did not report PZ and TZ lesions separately. Considering different dominant MRI sequences for these 2 anatomy zones, the detailed diagnostic for PZ and TZ lesions should be investigated in future study. Third, use of systematic and/or MRI-TRUS fusion targeted biopsy as the reference standard may lead to some lesions with positive pathology missed as which showed negative in MRI. Last, in this study we did not report the inter-reader agreement between radiologists, which is important for the standardized scoring system as it relates to reducing the variability of interpretation. However, because our main goal was to develop and validate nomogram for csPCa, investigation of the inter-reader agreement was beyond the scope of our study.