Cancer Health Center

Recurrent Low-Risk Organ Involvement

The optimal therapy for patients with relapsed or recurrent Langerhans cell histiocytosis (LCH) has not been determined. Several regimens exist. Patients with recurrent bone disease who reoccur months after stopping vinblastine and prednisone can benefit from treatment with a reinduction of vinblastine weekly and daily prednisone for 6 weeks. If there is no active disease or very little evidence of active disease, treatment can be changed to every 3 weeks with the addition of oral mercaptopurine nightly.[1] An alternative treatment regimen employs vincristine, prednisone, and cytosine arabinoside.[2] Cladribine (2-CdA) at 5 mg/m² /day for 5 days per course has also been shown to be effective therapy for recurrent low-risk LCH (multifocal bone and low-risk multisystem LCH) with very little toxicity as long as the therapy was limited to a maximum of six courses.[3]

A phase II trial of thalidomide for LCH patients (ten low-risk patients; six high-risk patients) who failed primary and at least one secondary regimen demonstrated complete (four out of ten) and partial (three out of ten) responses for the low-risk patients. Complete remission was defined as healing of bone lesions on plain radiographs (n = 3) or complete resolution of skin rash (n = 4, including 3 with bone lesions that had complete resolution). Partial response was defined as healing of bone lesion, but then worsening of a skin rash that was partially resolved. However, dose-limiting toxicities, such as neuropathy and neutropenia, may limit the overall usefulness of thalidomide.[4]

Indomethacin and pamidronate have also been used for recurrent LCH.[5,6,7]

Refractory High-Risk Organ Involvement

A new treatment plan is indicated when a patient with multisystem involvement shows progressive disease after 6 weeks of standard treatment, or has not had a partial response by 12 weeks. Data from the German-Austrian-Dutch Group studies have shown that these children have only a 10% chance of surviving.[8] Results of the LCH-II trial revealed that patients treated with vinblastine/prednisone who did not respond well by 6 weeks had a 27% chance of survival.[9][Level of evidence: 1iiA] Those treated with vinblastine/prednisone/etoposide with a good response at 6 weeks had a 52% chance of survival. Reports about the use of 2-CdA and 2'-deoxycoformycin as salvage therapies for LCH have been published.[3,10] In this trial, these drugs were more often effective for patients with bone, skin, or lymph node involvement. Only one-third of patients with LCH of the liver, bone marrow, spleen, or lung responded.[10] Another study demonstrated that patients with multiple reactivations or high-risk disease could be effectively treated with continuous infusion 2-CdA for 3 days.[11] Seven of ten patients on this trial required no more therapy. Two patients with multiorgan LCH that was resistant to other agents, including 2-CdA, responded to treatment with clofarabine.[12][Level of evidence: 3iiiDii]