Risk Factors for pT3a Prostate Cancerin the Patients With cT1-2 on PreoperativeMultiparametric Magnetic Resonance Imaging

ABSTRACT

Purpose@#Our study aimed to evaluate the predictive value of multiparametric magnetic resonance imaging (mpMRI)to assess the capsular extension of prostate cancer. Risk factors for extraprostatic invasion or microscopic invasionof bladder neck (pT3a stage) in the cases showing localized disease findings on MRI scan were also identified. @*Materials and Methods@#We identified 198 patients who underwent robot-assisted or conventional laparoscopicradical prostatectomy in our institute between June, 2016 and May, 2018. Altogether, 170 patients withpreoperational mpMRI scans and complete pathologic data were included. Positive and negative predictive valuesof mpMRI to detect capsular extension were estimated. Chi-square test was performed for ratio variables. Logisticregression analysis was performed to identify capsular invasion risk factors. @*Results@#Median age and prostate-specific antigen level were 68 years and 7.5 ng/mL, respectively. Based onfindings, 16 patients (9.4%) were identified as cT3a stage (unilateral or bilateral extraprostatic extension), whereas37 patients (21.8%) as pT3a stage. Positive and negative predictive values of mpMRI to detect capsular extensionwere 75.0% and 73.9%, respectively. In the logistic regression analysis, positive biopsy core rate was the significantpredictor for pT3a disease in the patients with negative capsular invasion findings on mpMRI (p<0.001). Accordingto receiver-operating characteristic curve (area under the curve=0.691, p=0.001), the positive biopsy core rateof 0.275 was the best threshold. @*Conclusions@#Multiparametric MRI is an appropriate test to predict pT3a disease preoperatively. The patients withpositive core rate over 0.275 may have pT3a diseases despite negative image findings.