Treatment of Childhood LCH
Multiple bone lesions; or combinations of skin, lymph node, or pituitary gland with or without bone lesions
- Vinblastine and prednisone: Six months of treatment with weekly vinblastine (6 mg/m2) for 7 weeks then every 3 weeks for good response. Prednisone (40 mg/m2) is given daily for 4 weeks then tapered over 2 weeks. Afterwards prednisone is given for 5 days at 40 mg/m2 every 3 weeks with the vinblastine injections. A short (<6 months) treatment course with only a single agent (e.g., prednisone) is not sufficient, and the number of relapses is higher. An 18% reactivation rate with a multidrug regimen for 6 months versus a historical reactivation rate of 50% to 80% with surgery alone, or with a single-drug treatment regimen has been reported. A comprehensive review of the DAL and Histiocyte Society clinical trials revealed a reactivation rate of 46% at 5 years.[Level of evidence: 3iii]. Most disease reactivations were in bone, skin, or other nonrisk locations.
- Pamidronate is also effective for treating LCH bone lesions. A nationwide survey from Japan described 16 children treated with bisphosphonates for bone LCH. All had bone disease; none had risk-organ disease. The majority received six courses of pamidronate at 1 mg/kg/course given at 4-week intervals. In 12 of 16 patients, all active lesions including skin (n = 3) and soft tissues (n = 3) resolved. Eight remained disease free at a median of 3.3 years.
Treatment of high-risk multisystem disease
Spleen, liver, and bone marrow (may or may not include skin, bone, lymph node, lung, or pituitary gland)
- The standard therapy length recommended for LCH involving the spleen, liver, or bone marrow (high-risk organs) is based upon LCH-I, LCH-II, and the DAL-HX-83 studies and varies from 6 months (LCH-I and LCH-II) to 1 year (DAL-HX-83).[11,14] In the LCH-II and HISTSOC-LCH-III studies, the standard arm consisted of vinblastine and prednisone as described above under multifocal bone, but 6-mercaptopurine was added to the continuation phase of the protocol. The LCH-II study was a randomized trial to compare treatment of patients with vinblastine, prednisone, and mercaptopurine or vinblastine, prednisone, mercaptopurine, and etoposide.[Level of evidence: 1iiA]
There was no statistical significance in outcomes (response at 6 weeks, 5-year probability of survival, relapses, and permanent consequences) between the two treatment groups. Hence, etoposide has not been used in subsequent Histiocyte Society trials. Late review of the results, however, has shown reduced mortality of patients with risk-organ involvement in the etoposide arm. Although controversial, a comparison of patients in the LCH-I trial with patients in the LCH-II trial suggested that increased treatment intensity promoted additional early responses and reduced mortality.
It is important to note that those studies included lungs as risk organs. However, subsequent analyses have shown that lung involvement lacks prognostic significance.
- The Japan LCH Study Group (JLSG) reported 5-year response and overall survival rates of 78% and 95%, respectively, for patients with multisystem disease treated on the JLSG-96 trial (6-week induction regimen of cytosine arabinoside, vincristine, and prednisolone followed by 6 months of maintenance therapy with cytarabine, vincristine, prednisolone, and low-dose intravenous methotrexate). If patients had a poor response to the initial regimen, they were switched to a salvage regimen of intensive combination doxorubicin, cyclophosphamide, methotrexate, vincristine, and prednisolone.
The important finding of this study was the decreased mortality compared with previous JLSG studies and to the LCH-II study, and was attributed to the early move to salvage therapy for patients with nonresponsive disease, improved salvage therapy, and better supportive care.