Osteosarcoma in very young children: experience of the Cooperative Osteosarcoma Study Group

This study was conducted to investigate presentation, treatment, and outcome in very young children with osteosarcoma.

The authors retrospectively analyzed the data of 2706 consecutive COSS patients with newly diagnosed osteosarcoma and identified 28 (1.0%) patients aged younger than 5 years at diagnosis. Demographic, diagnostic, tumor, treatment-related variables, response, and survival data were analyzed.

Of the 28 preschoolers, 27 presented with high-grade central osteosarcoma of an extremity, and 1 had a secondary osteosarcoma of the orbit. This analysis focused on the 27 patients with extremity tumors. The size of the primary was large (≥one-third of the involved bone) in 20 of 27 patients. Primary metastases were detected in 4 of 27 children. All patients received multiagent chemotherapy, and 11 of 18 analyzed tumors responded well (>90% necrosis) to neoadjuvant chemotherapy. Limb-sparing surgery was performed in 9 cases, ablative procedures were performed in 15, and, in 3 cases, no local surgery was performed. With a median follow-up of 4 years (6.2 years for survivors), 13 patients were alive. Four patients never achieved a complete remission, and 11 developed recurrences; 14 of these 15 patients died. Five-year overall and event-free survival probabilities were 51% (standard error of the mean [SE], 10%) and 48% (SE, 10%). Better survival was correlated with good response to chemotherapy and later time period of diagnosis.

Osteosarcoma is extremely rare in preschool children. These patients often have large tumors that may require mutilating resections. Prognosis is in the range of that reported for older patients.