PFS estimates for adults with LCH. (A) Entire cohort, (B) based on year of diagnosis, (C) based on BRAF V600E mutational status, and (D) based on classification of disease subtype. MS/MF RO-, multisystem or multifocal risk organ negative; neg, negative; pos, positive; SS-Pulm, single-system pulmonary; RO+, risk organ positive.