Timo Soeterik

67 Impact of MRI on Risk Classification TABLE 2 Risk group migration patterns in patients undergoing mpMRI in the overall population Risk group based on MRI Low N (%) Intermediate N (%) High (localized) N (%) High (locally advanced) N (%) Total N (%) Based on DRE Low 357 (80) 9 (2) 39 (9) 43 (10) 448 (27) Intermediate 5 (1) 409 (62) 66 (10) 178 (27) 658 (39) High (localized) 3 (1) 7 (2) 181 (52) 158 (45) 349 (21) High (locally advanced) 3 (1) 10 (4) 15 (7) 200 (88) 228 (14) 368 (22) 435 (26) 301 (18) 579 (34) 1683 (100) EAU risk group migration Percentages of patients classified according to the EAU risk classification based on DRE as well as mpMRI are presented in Table 2. Risk group migration based on mpMRI findings occurred in 536 of 1683 (32%) of patients. Respectively 493 (29%) patients migrated to a higher risk group and 43 (3%) patients to a lower risk group. Upstaging occurred respectively among 21% of patients initially classified as low-risk, 37% of the intermediate-risk and 45% of the localised high-risk. Presence of stage ≥T3a disease on mpMRI (and subsequent migration to locally advanced high-risk) was the reason for upstaging in 378 of 493 (77%). Migration to locally advanced high-risk occurred in respectively 10% of the low-risk, 27% intermediate-risk and 45% of the localised high- risk patients (Table 2). Accuracy of DRE and MRI for detection of non-organ-confined disease RARP was the primary choice of treatment in 552 of 1683 (33%) patients. Of these, 509 of 552 (92%) underwent mpMRI within 6 months before surgery, including 3 patients that underwent surgery elsewhere with unavailable pathology reports. A total of 506 patients with complete study data treated with RARP were included for the analysis (Table S2). Stage migration patterns in the RARP subset where comparable to those observed in the overall population (Table S3). Sensitivity of mpMRI and DRE for the detection of stage ≥T3a in this subset were respectively 51% and 12%, p < 0.001 (Table 3). Specificity rates were respectively 97% and 82% for DRE and mpMRI ( p < 0.001). Cumulative rate of true positive and true negative stage ≥T3a predictions was higher for mpMRI compared to DRE (341 of 506 [67%] vs 294 of 506 [58%], p < 0.001). Diagnostic accuracy measures of both DRE and mpMRI for detection of nonorgan-confined disease (stage ≥T3a) per EAU risk group are presented in Table 3. 4