Osteosarcoma in pre-adolescents: diagnostic interval, metastasis frequency, and treatment abandonment.

Background: osteosarcoma is the most common malignant bone tumor, but it is rare before adolescence. The clinical behavior of the tumor that develops in pre-adolescents may differ from that seen during adolescence.

Method: This is a retrospective study of pre-adolescents with osteosarcoma diagnosed in a tertiary-level hospital. The patients were compared with adolescents diagnosed during the same period.

Results: we analyzed 149 patients (forty-four pre-adolescents). The diagnostic interval median was 7 weeks in pre-adolescents and 12 weeks in adolescents (p = 0.002). Forty-four patients had metastases at diagnosis (ten pre-adolescents) (p = 0.23). Limb-salvage surgery was performed on sixteen patients (two pre-adolescents). Fifty-six patients (thirteen pre-adolescents) abandoned the treatment (p = 0.18). Overall survival was 63 months in pre-adolescents and 52 months in adolescents (p = 0.301).

Conclusion: We only found differences in the diagnostic interval, which was shorter in pre-adolescent patients. Studies with a larger number of pre-adolescents are necessary to determine the differences in the characteristics of the disease in adolescent patients.