Treatment of Multifocal Osseous LCH in Adults When Bisphosphonates, Methotrexate, or Radiation Have Not Achieved Disease Control
Clinical Scenario
This protocol applies to adults presenting with multifocal osseous Langerhans cell histiocytosis — bone-only disease characterised by multiple lytic osseous lesions — in whom initial bone-directed therapy has not achieved the expected treatment goals.
Why Escalation Is Required
Standard first-line management of multifocal osseous LCH includes bisphosphonates (alendronate, pamidronate, or zoledronate), oral low-dose methotrexate, or hydroxyurea, plus radiation therapy when fewer than three lesions are safely amenable to radiation. This protocol is indicated when that prior therapy has failed to achieve:
- Resolution of bone pain
- Radiographic ossification or normalization of bone lesions
- Adequate response on FDG-PET/CT at 2–3 months
References
DOI: 10.1182/blood.2021014343
- For multifocal osseous LCH, recommended treatments are radiation therapy (<3 lesions safely amenable to radiation), bisphosphonates, or systemic chemotherapy.
- For disease recurrence not amenable to local therapies or unresponsive to immunosuppressive agents, systemic chemotherapy is recommended.
- Among systemic treatment options for LCH, chemotherapy using either cladribine or cytarabine is preferred because of relatively high overall response rates and the potential for long-term remissions with limited cycles of treatment.
- For initially FDG PET avid LCH, it is recommended to repeat an FDG PET-based imaging study for assessment of disease response after 2–3 mo of initiation of therapy, with subsequent imaging frequency tailored individually based on the specific clinical scenario.