Open Access

Milen Minkov, Ulrike Pötschger, Nirav Thacker, Itziar Astigarraga, Jorge Braier, Jean Donadieu, Jan-Inge Henter, Thomas Lehrnbecher, Carlos Rodriguez-Galindo, Elena Sieni, Vasanta Nanduri, Cor van den Bos, Oussama Abla

• Objective: To evaluate the prognostic impact of gastrointestinal involvement on the survival of children with Langerhans cell histiocytosis (GI-LCH) registered with the international clinical trials of the Histiocyte Society. Study design: This was a retrospective analysis of 2414 pediatric patients registered onto the consecutive trials DAL-HX 83, DAL-HX 90, LCH-I, LCH-II, and LCH-III. Results: Among the 1289 patients with single-system LCH, there was no single case confined to the GI tract; 114 of 1125 (10%) patients with multisystem LCH (MS-LCH) had GI-LCH at initial presentation. GI-LCH was significantly more common in children aged <2 years at diagnosis (13% vs 6% in those aged >2 years; P < .001) and in those with risk organ involvement (15% vs 6% in those without risk organ involvement; P < .001). The 5-year overall survival (OS) in patients without risk organ involvement was excellent irrespective of GI disease (98% vs 97% in patients with GI-LCH; P = .789). In patients with risk organ involvement, the 5-year OS was 51% in 70 patients with GI-LCH vs 72% in 394 patients without GI-LCH (P < .001). Conclusions: GI-LCH has an additive unfavorable prognostic impact in children with MS-LCH and risk organ involvement. The emerding need for more intensive or alternative treatments mandates prospective evaluation.