Purpose: The purpose of this study was to determine the toxicities of and responses to high-dose busulfan and cyclophosphamide with autologous bone marrow transplant (ABMT) in patients with recurrent or refractory pediatric solid tumors.
Patients and methods: We treated 18 patients (ages, 2 to 38 years; median, 14) who had tumors that were resistant to conventional chemotherapy and radiotherapy with busulfan 16 mg/kg and cyclophosphamide 200 mg/kg. Seventeen patients received bone marrow purged with 4-hydroperoxycyclophosphamide; one received unpurged marrow.
Results: Despite extensive prior treatment, including radiotherapy in 16 patients, toxicity generally was acceptable. For seven patients with measurable disease, there were three partial responses of 2, 10, and 20 months' duration, three patients with stable disease (SD), and one early, toxic death. Of the 11 patients with no measurable disease at the time of transplantation, one patient with osteosarcoma continues in remission at 57+ months and one third of the patients survived for at least 16 months. Mucositis was the predominant nonhematopoietic toxicity.
Conclusion: Although the high-dose busulfan and cyclophosphamide combination showed modest activity, changes in the preparative regimen should be considered to improve the response rate in refractory tumors.