Timo Soeterik

65 Impact of MRI on Risk Classification Accuracy of DRE and MRI for detection of non-organ-confined disease Sensitivity, specificity, negative predictive value and positive predictive value were assessed for DRE as well as mpMRI for prediction of non-organ-confined disease (pathological tumour stage ≥T3a). Analysis was done in the subset of patients that underwent RARP as primary treatment (within 6 months of performed DRE as well as MRI), using histopathological evaluation of the prostate specimen as the gold standard. Prognostic impact of non-organ-confined disease observed on mpMRI Potential prognostic impact of non-organ-confined disease (stage ≥T3a) on mpMRI was assessed in patients undergoing RARP, between January 1, 2017 and July 1, 2018. Patients treated from July and onwards were excluded due to limited follow-up time. Biochemical recurrence (BCR) rates were assessed per D’Amico risk group, stratifying for presence of stage ≥T3a on mpMRI per risk group. BCR after RARP was defined as a postoperative PSA ≥ 0.2 ng/ml. Statistical analysis Diagnostic accuracy measures (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV]) were established for the detection of stage ≥T3a for both DRE and mpMRI, using McNemar’s Test to assess statistical significance of differences. Diagnostic accuracy of both modalities, in terms of area under the receiver operating curve (AUC), was also evaluated. Biochemical progression-free survival was assessed by Kaplan-Meier using the log-rank test for assessing statistical significant differences. A p -value of < 0.05 was considered significant. Statistical analysis was done using IBM SPSS for windows, Version 24.0 (IBM Corp., Armonk, N.Y., USA). RESULTS Study population A total of 2383 patients were identified fulfilling the inclusion criteria. In total, 1740 (73%) underwent mpMRI during diagnostic work-up, of which 1683 of 1740 (97%) had complete baseline data, who were included for analysis (Figure S1). Patient baseline characteristics are presented in Table 1. 4