Non-metastatic osteosarcoma of the extremities in children aged 5 years or younger.

Background: The occurrence of high-grade osteosarcoma is rare in children aged 5 years or younger and only limited series or case reports have been described.

Methods: The records of patients aged 5 years or younger with non-metastatic high-grade osteosarcoma of the extremities treated with surgery and adjuvant or neo-adjuvant chemotherapy at Rizzoli Institute between 1972 and 1999 were retrospectively evaluated in relation to gender, primary tumor site, histological subtype, surgical treatment, chemotherapy-induced tumor necrosis, 5- and 10-year event-free survival (EFS), and rate of local recurrence. Data were compared to patients aged 6-40 years entered with the same diagnosis and over the same time interval.

Results: Data from 20 patients were collected. Comparing these data with those from 1,106 patients 6-40 years of age only two main differences resulted: the younger group showed a higher rate for fibroblastic subtype (P < 0.01) and for amputation surgery (P < 0.01). Among the two groups, no statistical difference was observed for the 5-year EFS (60% vs. 53.8%; P = 0.6) and 10-year EFS (60% vs. 52.1%; P = 0.5). The rate of local recurrence was 5.0% and 5.4%.

Conclusions: These findings suggest that in non-metastatic osteosarcoma of the extremities outcome and clinical characteristics are similar among children 5 years of age or younger and older patients. However, in the younger group we have observed a significant higher rate of fibroblastic subtype as well as a significant higher rate of mutilating surgery. Pediatr Blood Cancer.