Introduction: Currently, AS programmes vary across the world, with different timings in terms of follow-up on MRI and biopsy. The PRECISE criteria provide a dedicated 1-to-5 scale to evaluate the radiological change on serial MRI: a PRECISE score of 1 or 2 denotes radiological regression, PRECISE 3 indicates stability and PRECISE 4 or 5 implies progression. We report the first validation of the PRECISE score in a multicentre international setting. Methods: We collected data from 22 centres across the world and applied two entry criteria: i) at least 2 MR scans (baseline and follow-up); ii) at least 2 biopsies (baseline and follow-up, the latter after the second MR). Local radiologists reported the scans using PRECISE. Histological progression was defined as any increase in Gleason Score from baseline biopsy. Progression-free survival (PFS) was estimated using Kaplan-Meier curves with landmark time starting from date of first follow-up MRI (i.e., second MR), and multivariable Cox proportional hazards model tested the predictive role of PRECISE. Results: A total of 1,556 patients were included, 1389 (89%) of which had Gleason 3+3 and 167 (11%) had Gleason = 3+4 at baseline. Median follow-up was 48 months, and 513 (33%) patients experienced histological progression. The overall 5- and 10-year progression-free survival (PFS) were 66% and 41%, with time starting at diagnosis. For PRECISE 1-2 (n=158), PFS was 88% at 2 years from first follow-up MRI and 77% at 5 years, while for PRECISE 4-5 (n=413), PFS was 52% and 35%. In those with PRECISE 3 [stability] and visible lesions (n=597), 2- and 5-year PFS was 76% and 50%, while for PRECISE 3 [stability] and non-visible lesions (n=388), PFS was similar to PRECISE 1-2 (2- and 5-year PFS: 91% and 80%) (Log Rank p<0.001). At multivariable analysis, PRECISE 4-5 remained an independent predictor of histological progression (HR: 2.63; p<0.0001). Conclusions: Our work has validated the PRECISE score in a multicentre setting and has the potential to be included in future risk models that incorporate both clinical and radiological data to fully benefit from prostate MRI and targeted biopsies. SOURCE OF Funding: Prostate Cancer Foundation / CRIS Cancer Foundation (Francesco Giganti is a recipient of the 2020 Young Investigator Award).
