MP43-14 EXTERNAL VALIDATION OF A MODEL PREDICTING INCREASE IN GLEASON GRADE FOR MEN ON ACTIVE SURVEILLANCE IN THE GAP3 CONSORTIUM DATABASE. (1st May 2022) - Nieboer, Daan; de Vos, Ivo; Lee, Lui Shiong; Stricker, Phillip; Frydenburg, Mark; Bjartell, Anders; Rubio-Briones, Jose; Semjonow, Axel; Rannikko, Antti; van Hemelrijck, Mieke; Pavlovich, Christian; Carroll, Peter; et al.