Objective:To assess the rationality of the maximum lesion diameter of 15 mm in prostate imaging reporting and data system(PI-RADS)as a criterion for upgrading a lesion from category 4 to 5 and improve it to enhance the prediction of clinically significant prostate cancer(csPCa).Methods:In this study,the patients who underwent prostate magnetic resonance imaging(MRI)and prostate biopsy at Peking University First Hospital from 2019 to 2022 as a development cohort,and the patients in 2023 as a validation cohort were reviewed.The localization and maximum diameter of the lesion were fully evalua-ted.The area under the curve(AUC)and the cut-off value of the maximum diameter of the lesion to pre-dict the detection of csPCa were calculated from the receiver operating characteristics(ROC)curve.Confounding factors were reduced by propensity score matching(PSM).Diagnostic efficacy was com-pared in the validation cohort.Results:Of the 589 patients in the development cohort,358(60.8％)lesions were located in the peripheral zone and 231(39.2％)were located in the transition zone,and 496(84.2％)patients detected csPCa.The median diameter of the lesions in the peripheral zone was smaller than that in the transition zone(14 mm vs.19 mm,P＜0.001).In the ROC analysis of the maximal diameter on the csPCa prediction,there was no statistically significant difference between the peri-pheral zone(AUC=0.709)and the transition zone(AUC=0.673,P=0.585),and the cut-off values were calculated to be 11.5 mm for the peripheral zone and 16.5 mm for the migrating zone.By calcula-ting the Youden index for the cut-off values in the validation cohort,we found that the categorisation by lesion location led to better predictive results.Finally,the net reclassification index(NRI)was 0.170.Conclusion:15 mm as a criterion for upgrading the PI-RADS score from 4 to 5 is reasonable but too general.The cut-off value for peripheral zone lesions is smaller than that in transitional zone.In the future consideration could be given to setting separate cut-off values for lesions in different locations.

Objective:To investigate the diagnostic efficacy of targeted biopsy combined with regional systematic biopsy in prostate cancer(PCa)in patients with prostate imaging reporting and data system v2.1(PI-RADS v2.1)4-5.Methods:From January 2023 to October 2023,patients who underwent prostate biopsy for the first time with total prostate specific antigen(tPSA)≤20 ng/mL and had a multi-parametric magnetic resonance imaging(mpMRI)PI-RADS of 4-5 in Peking University First Hospital were prospectively collected.All the patients underwent transrectal ultrasound-guided cognitive fusion tar-geted biopsy(3 cores)followed by systematic biopsy(12 cores).Various hypothetical biopsy schemes were defined based on different biopsy sites.The detection effectiveness of targeted biopsy combined with regional systematic biopsy and other biopsy schemes for prostate cancer were compared using Cochran's Q and McNemar tests.Results:A total of 255 patients were enrolled,of whom 204(80.0％)were de-tected with prostate adenocarcinoma and 187(73.3％)were clinically significant with prostate cancer(csPCa).The detection rate of PCa with targeted biopsy was significantly lower than that of targeted biopsy combined with 12-core system biopsy(77.3％vs.80.0％,P=0.016),and 71.4％(5/7)of the missed patients was csPCa.There was no significant difference in the detection rate between targeted biopsy combined with 4-core regional system biopsy and 12-core system biopsy(P＞0.999),and 1 case of csPCa and clinically insignificant prostate cancer(cisPCa)were missed.There was no significant difference in the detection rate of PCa between targeted combined regional system biopsy and targeted combined lateral or traditional 6-core system biopsy and the number of cores were reduced.Missed diag-nosis of targeted biopsy was correlated with the maximum diameter of the lesion(OR=0.086,95％CI:0.013-0.562,P=0.010).For the patients with PI-RADS 5,only 1 case of PCa was missed in 122 cases by targeted biopsy alone.For patients with PI-RADS 4,6 PCa cases were missed among the 133 patients with targeted biopsy alone,and 1 case of csPCa and cisPCa were missed by targeted biopsy com-bined with regional system biopsy.The statistics of positive core counts for different biopsy schemes indi-cated that targeted combined regional systematic biopsy had a higher proportion of positive cores second only to targeted biopsy alone.Conclusion:Targeted biopsy combined with regional systematic biopsy has high diagnostic efficacy in patients with PI-RADS 4-5 and can be considered as one of the improved schemes for combined biopsy.Targeted biopsy alone is also a feasible option for patients for patients with a PI-RADS score of 5.