Treatment of Childhood LCH
Skull lesions in the mastoid, temporal, or orbital bones
The purpose of treating patients with skull lesions in the mastoid, temporal, or orbital bones is to decrease the chance of developing diabetes insipidus and other long-term problems, although the efficacy of this, and the optimal length of therapy, have yet to be proven in a prospective trial.
- Twelve months of vinblastine and prednisone (based upon comparative results noted above regarding DAL-HX trials versus the LCH-I and LCH-II studies): Weekly vinblastine (6 mg/m2) for 7 weeks then every 3 weeks for good response. Daily prednisone (40 mg/m2) for 4 weeks then tapered over 2 weeks. Afterward prednisone is given for 5 days at 40 mg/m2 every 3 weeks with the vinblastine injections.
- There is some controversy about whether systemic therapy is required for the first presentation with unifocal bone even in the central nervous system (CNS) risk bones. Ear, nose, and throat surgeons have reported a series of patients with orbital or mastoid lesions who received only surgical curettage. None of these patients developed diabetes insipidus. However, when comparing the incidence rates of diabetes insipidus in patients who received little or no chemotherapy (20%–50% incidence of diabetes insipidus) versus diabetes insipidus incidence rates reported by the German-Austrian-Dutch (Deutsche Arbeits-gemeinschaft für Leukaemieforschung und-therapie im Kindesalter [DAL]) Group HX-83 trial (10% incidence of diabetes insipidus in patients treated for LCH), it appears that the weight of evidence from the DAL HX-83 trial supports treatment to prevent diabetes insipidus in patients with LCH of the mastoid, temporal, or orbital bones.[13,14] It should be noted, however, that the DAL HX studies used more drugs and treated for a duration of 12 months. Nonetheless, the CNS study group of the Histiocyte Society believes prevention of the potentially devastating consequences of CNS and endocrine disease with relatively low-toxicity chemotherapy is worthwhile; acknowledging that the overall level of evidence is low (Level of evidence: 3iii) and that prospective trials are needed.
Vertebral or femoral bone lesions at risk for collapse
- Radiation therapy is indicated for patients with bone lesions of the vertebrae or femoral neck, which are at risk of collapse or fracture.[15,16] Low-dose radiation therapy may be used to try to promote resolution in an isolated vertebral or femoral neck lesion at risk for fracture, where chemotherapy is not usually indicated (single bone lesion). Despite the low dose required (700–1,000 cGy), radiation therapy should be used with caution in the area of the thyroid gland, brain, or any growth plates.
- When instability of the cervical vertebrae and neurologic symptoms are present, bracing or spinal fusion may be needed. Patients with soft tissue extension from the vertebral lesions are often treated successfully with chemotherapy.[Level of evidence: 3iiDiii]