Establishment Of A New Model For Predicting The Result Of Prostate Biopsy Based On PI-RADS V2

Objective: To explore a predictive nomogram for the result of prostate biopsy based on Prostate Imaging Reporting and Data System version 2(PI-RADS v2)combined with prostate specific antigen(PSA)and its related parameters,and to assess its ability to diagnose prostate cancer by internal validation.Methods: We retrospectively analyzed the clinical data of 509 patients who underwent transrectal prostate biopsy guided by B-ultrasonography during the period from January 2014 to December 2018 in the Department of Urology,First Affiliated Hospital of Xiamen University,and scored the main lesions of the prostate according to PI-RADS v2.Of these patients,we randomly selected 80%(407 cases)as development group,and the other 20%(102 cases)as validation group.Univariate and multivariate logistic regression analysis of the development group was performed to identify the independent influence factors that can predict prostate cancer(PCa)and high-grade prostate cancer(HGPCa),thereby establishing a predictive model for the result of prostate biopsy.Diagnostic performance was evaluated by analyzing the receiver operating characteristic(ROC)curve,calibration curve and decision curve,and compared to PSA and its related parameters.Results: Among the 509 patients enrolled in the study,the detection rate of PCa was 43.0%(219/509),and the HGPCa was 34.2%(174/509).In the development group,the logistic regression analysis demonstrated that patient age,free to total PSA(f/t PSA),prostate volume(PV),PSA density(PSAD),digital rectal examination(DRE)texture,transabdominal ultrasound(TAUS)with or without hypoechoic,and PI-RADS v2 were independent factors for PCa(P<0.05).The nomogram based on all variables was established.In the development group,validation group and t PSA was between 4.0-20.0 ng/ml,the ROC curve analysis indicated that the area under the curve(AUC)of the nomogram established by PI-RADS v2 to predict the PCa was greater than PSA and its related parameters.The calibration curve of the nomogram indicated that the prediction curve was basically fitted to the standard curve,and the Hosmer-Lemeshow showed that ?2=5.434,P=0.710,both suggested that the prediction model had better calibration ablity.The decision curve showed that the model based on PI-RADS v2 had high clinical application value.Further analysis of the influencing factors of HGPCa showed that patient age,t PSA,PSAD,DRE texture,and PI-RADS v2 were independent factors for HGPCa(P<0.05).The nomogram based on all variables was established.The model's ROC curve,calibration curve and decion curve all suggested that the nomogram based on PI-RADS v2 had high diagnostic performance and calibration ability for HGPCa.Conclusion: The nomogram based on PI-RADS v2 could significantly improve the detection rate of the prostate cancer and high-grade prostate cancer.It had better diagnostic value than PSA and its related parameters,and could reduce unnecessary prostate biopsy to some extent.It also provided important guidance for the prostate cancer on clinical treatment of patients.