We report the use of vincristine sulfate, vinblastine sulfate, and cyclophosphamide in the treatment of children with histiocytosis X. No children with solitary eosinophilic granulomas are included in this study. The complete remission rates for the three drugs were 50%, 20%, and 36%, respectively; and the complete remission plus partial remission rates are 50%, 55%, and 63%, respectively. Because of the small numbers of patients involved, and the design of the study, we could reach no conclusions regarding the relative efficacy of the drugs. We discuss factors influencing the response and present tabulated data regarding age, degree of involvement, duration of therapy, and result of therapy for each patient. Histiocytosis X is the term which has been generally accepted to encompass the three related childhood syndromes: Letterer-Siwe syndrome, Hand-Schüller-Christian syndrome, and eosinophilic granuloma. The Southwest Cancer Chemotherapy Study Group undertook the study of this group of patients to determine therapeutic responses to three drug treatment programs.Spontaneous remissions in children with histiocytosis X have been re¬ ported, as have complete remissions after antibiotic therapy. These facts, plus the fact that the disease is one which is characterized by periods of increased activity followed by periods of decreased activity and vice versa, make evaluation of response to ther¬ apy difficult.
Material and MethodsChildren under 15 years of age with the histologie diagnosis of histiocytosis X were entered into these studies. No chil¬ dren with single eosinophilic granulomas are included, and subclassification into Hand-Schüller-Christian and LettererSiwe syndromes was not made. The degree of involvement is shown in Tables 1-3. All had active disease manifested by progres¬ sion of lesions. The three drugs evaluated were vincristine sulfate, vinblastine sul¬ fate, and cyclophosphamide, used singly, and in some cases, sequentially/The study was not randomized, and the study drug was chosen at the discretion of the in¬ vestigator.Vincristine sulfate was given intra¬ venously at a dose level of 2.0 mg/sq m weekly.Vinblastine sulfate was given intra¬ venously once weekly. The initial dose was 6.5 mg/sq m. If the white blood cell count (WBC) did not fall below 3,500/cu mm, the dose was increased to 9.8 mg/sq m given intravenously weekly. If neutropenia oc¬ curred at the higher dose level, the dose was reduced to 6.5 mg/sq m given intra¬ venously weekly.