Clinical Characteristics And Treatment Outcome Of Children With Langerhans Cell Histiocytosis

Objective:To summarize and analyze the clinical characteristics and treatment outcome of children with Langerhans cell histiocytosis(LCH).Methods:From January 2007 to December 2013,newly diagnosed patients with histopathologically-confirmed LCH were enrolled in this retrospective study.All patients were treated on the SCMC-LCH protocol(LCH II modified protocol).Survival was determined using the Kaplan-Meier method with differences between different groups compared using the log-rank test.Prognostic relevance of different parameters were analyzed by Cox proportional hazard model.Results:(1)Totally 135 patients were diagnosed to have multi-system Langerhans cell histiocytosis(MS-LCH).Of the 135 patients(89 boys and 46 girls),the median age was 3 years(range,3 months to 14 years).The 3-year event free survival(EFS)and 3-year overall survival(OS)for all cases were(62±5)%and(82±4)%,respectively.In univariate analysis,age at presentation(≤2 years)(X~2=12.600,P=0.000),risk organ involvement(X~2=11.583,P=0.001),and poor response at week6(X~2=38.711,P=0.000)were associated with lower survival rates.In multivariate analysis,age at presentation was not an independent prognostic risk factor(OR=1.013,P=0.207).There were 36 patients(27%,36/135)who experienced disease progression or relapse.The time to disease progression or relapse ranged from1 to 31 months from the initial diagnosis(median,6 months).Significantly lower OS(18±3)%was observed in 20 patients with risk organ involvement at progression/relapse.(2)Totally 74 patients were diagnosed to have single-system Langerhans cell histiocytosis(SS-LCH),the median age was 30 months(range 1months to 77 months).The 5-year event free survival(EFS)and 5-year overall survival(OS)for all cases were(84±6)%and 100%,respectively.There were 10patients(14%,10/74)who experienced disease progression or relapse.The time to disease progression or relapse ranged from 2 to 33 months from the initial diagnosis(median,7.5 months).Patients with skull involvement at diagnosis was associated with disease progression/relapse(X~2=5.601,P=0.036).(3)Pulmonary involvement in MS-LCH was present at diagnosis in 31 patients(23%).In multivariate analysis,pulmonary involvement was not an independent prognostic factor(OR=0.828,P=0.746).Conclusion:LCH has an extremely heterogeneous spectrum of clinical presentations with an unpredictable course and outcome.The SS-LCH generally have good prognosis.Pulmonary involvement at diagnosis had no significant impact on survival rates.Risk organ involvement and poor response at week 6 were the strongest prognostic factors for patients with LCH.Second initial treatment for patients with poor response at week 6 and effective salvage therapy need to be taken into account in our future studies.