Additive Prognostic Impact of Gastrointestinal Involvement in Severe Multisystem Langerhans Cell Histiocytosis

Area of Science:

• Pediatric Oncology
• Histiocytosis Research
• Clinical Trials in Childhood Cancer

Background:

• Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disease.
• Gastrointestinal (GI) involvement in pediatric LCH can affect prognosis.
• Understanding the prognostic impact of GI-LCH is crucial for treatment stratification.

Purpose of the Study:

• To assess the prognostic significance of gastrointestinal involvement in pediatric Langerhans cell histiocytosis (GI-LCH).
• To evaluate the impact of GI-LCH on survival rates in children treated within international clinical trials.

Main Methods:

• Retrospective analysis of 2414 pediatric patients from consecutive Histiocyte Society clinical trials (DAL-HX 83, DAL-HX 90, LCH-I, LCH-II, LCH-III).
• Evaluation of gastrointestinal involvement at initial presentation in patients with single-system LCH and multisystem LCH (MS-LCH).
• Comparison of 5-year overall survival (OS) based on the presence or absence of GI-LCH, particularly in patients with and without risk organ involvement.

Main Results:

• Gastrointestinal involvement was not observed in single-system LCH but occurred in 10% of multisystem LCH cases.
• GI-LCH was more frequent in younger children (<2 years) and those with risk organ involvement.
• In patients with risk organ involvement, 5-year OS was significantly lower with GI-LCH (51%) compared to without GI-LCH (72%).

Conclusions:

• Gastrointestinal involvement in pediatric multisystem Langerhans cell histiocytosis confers an additional unfavorable prognostic impact, particularly when risk organs are involved.
• The findings highlight the need for prospective evaluation of more intensive or alternative treatment strategies for children with GI-LCH and risk organ involvement.