Abstract: Objective? To evaluate the efficacy of combined chemotherapy with cytarabine (Ara-C) for children with refractory Langerhans cell histiocytosis (LCH). Methods The clinical data of patients with refractory LCH in Children's Hospital of Chongqing Medical University were retrospectively analyzed to evaluate the curative effect. Results A total of 11 patients with refractory LCH were included, with a male-to-female ratio of 6 to 5 , the median diagnostic age was 22 months ( 5 - 157 months), with median follow-up duration of 32 months ( 17 - 75 months). All of the patients were MS-LCH. After first-line treatment, 9 patients had disease progression ( 8 patients had skeletal progression), and 2 patients had stable disease. All patients were treated with combined Ara-C chemotherapy. The overall response rate was 91% ( 1 patient was cured, 9 patients were improved, and 1 patient was in a stable state), the overall survival rate was 100%. For patients with central nervous system (CNS) involvement (n= 10 ), 9 patients were accompanied by CNS mass at the first diagnosis, and 5 of the 9 patients had a complete regression of the CNS mass after the treatment. And two patients had diabetes insipidus as sequelae. Conclusion Ara-C combined with chemotherapy for refractory LCH had a high response rate, and it also had a better effect for patients with CNS involvement.

Key words: Langerhans cell histiocytosis;? cytarabine;? refractory;? central nervous system;? treatment