2.2 Therapeutic regimen
Based on the number of involved organs/systems, LCH was categorized into
two types: single-system (SS-LCH) with unifocal or multifocal
involvement and multi-system (MS-LCH) with two or more organs/systems
involvements. MS-LCH was classified as risk organ (RO) positive (liver,
spleen, and/or hematopoietic system) or negative according to LCH
extent26.
Most of the enrolled patients received the standard first-line
chemotherapy, based on the LCH-III protocols27-29.
Briefly, the first-line therapy comprised one or two six-week courses of
initial induction therapy (vindesine-steroid combination) and
maintenance therapy (vindesine, prednisone, with or without
6-mercaptopurine). The overall duration of first-line treatment was 12
months or six months (for non-CNS-risk SS-LCH with good response to the
first induction treatment). BRAF inhibitor dabrafenib was directly
administered to those BRAF -V600E-mutated MS-LCH patients who were
under two years old or unable to endure the standard
chemotherapy30. Treatment response were assessed
according to International LCH study Group
criteria8,26.