The 5-Year EFS of Multisystem LCH With Risk-Organ Involvement Is Suboptimal: A Single-center Experience From India

Area of Science:

• Pediatric Oncology
• Hematology
• Immunology

Background:

• Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disorder of myeloid dendritic cells.
• Effective management strategies for LCH are crucial, particularly for high-risk patient groups.
• The LCH-III treatment platform provides a standardized approach to LCH management.

Purpose of the Study:

• To evaluate an 8-year single-center experience managing pediatric LCH using the LCH-III platform.
• To assess treatment outcomes, survival rates, and relapse frequencies across different LCH risk groups.
• To identify prognostic factors influencing mortality and event-free survival in LCH patients.

Main Methods:

• Retrospective review of pediatric LCH cases diagnosed between 2006 and 2013.
• Patients were categorized into three groups based on LCH-III criteria: multisystem with risk-organ involvement (Group 1), multisystem without risk-organ involvement (Group 2), and single-system/multifocal bone disease (Group 3).
• Treatment protocols varied by group, involving vinblastine, prednisolone, and 6-mercaptopurine, with treatment durations ranging from 6 months to 12 months.

Main Results:

• Of 49 patients, 24 were in Group 1, 14 in Group 2, and 11 in Group 3.
• Seven deaths occurred, all in Group 1, with mortality linked to poor initial response or progressive disease.
• Five-year event-free survival was significantly lower in Group 1 (29.3%) compared to Groups 2 (58.9%) and 3 (69.3%). Overall survival was 68.9% for Group 1 versus 100% for Groups 2/3.

Conclusions:

• Multisystem LCH with risk-organ involvement (Group 1) is associated with poorer prognoses and higher mortality.
• Early treatment response is a critical determinant of survival in high-risk LCH patients.
• The LCH-III platform provides a framework for managing LCH, but outcomes for high-risk patients require further optimization.