“…Our work represents the first comparison of these newer staging systems to each other, and the first to externally validate both of them simultaneously in a large multi-center contemporary United States cohort treated with modern triplet therapy. Previous work has evaluated these staging systems in small single-center analyses, such as two single-center reports from China evaluating the performance of MASS in 94 [ 9 ] and 307 patients [ 10 ], respectively. Similar single-center studies have also evaluated the performance of R2-ISS in cohorts from China and Japan [ 11 , 12 ].…”