Treatment of metastatic osteosarcoma at diagnosis: A Pediatric Oncology Group Study

Purpose: To estimate the duration of survival (S) of patients with metastatic osteosarcoma (MOS) at diagnosis treated with a multiagent, ifosfamide-containing chemotherapeutic and surgical regimen and to evaluate the toxicity of this regimen. Patients and Methods: Thirty patients aged younger than 30 years received two courses of ifosfamide followed by surgery on the primary tumor and metastatic sites. Patients then received a postsurgical multiagent chemotherapeutic regimen that consisted of high-dose methotrexate (HDMTX), ifosfamide, doxorubicin, and cisplatin. Results: The 5- year event-free survival (EFS) rate was 46.7% (95% confidence interval [CI]; 28.5 to 64.9) and 5-year S rate was 53.3% (95% CI; 35.1 to 71.5). Three patients with bone metastases and one patient with lymph node metastases died. Twenty-six patients presented with pulmonary metastatic nodules only. Eight of these patients had at least eight nodules at diagnosis and had an estimated 5-year EFS rate of 25.0% compared with 66.7% for the 18 patients with less than eight nodules (P = .06). Fourteen patients presented with bilateral lung metastases and had a 5-year EFS rate of 35.7% compared with the 12 patients who presented with unilateral involvement and had a 5-year EFS rate of 75.0% (P = .03). The hematopoietic toxicity experienced by the patients during the entire regimen was relatively mild. Seven patients had renal toxicity characterized by hypophosphatemia and/or hypokalemia. Conclusion: This ifosfamide-containing regimen is tolerable and effective in the treatment of patients with osteosarcoma (OS) who present with lung metastases. However, better regimens are required for this group of patients.