Fifteen Years' Experience of the Brazilian Osteosarcoma Treatment Group (BOTG): A Contribution from an Emerging Country.

Purpose: Little information is available regarding the tumor features, prognostic factors, and treatment results in children and adolescents and young adults (AYAs) with osteosarcoma diagnosed in developing countries. We reviewed the results of three observational cohorts of osteosarcoma patients treated in an emerging country.
Methods: A total of 604 patients below the age of 30 years with high-grade osteosarcoma were prospectively enrolled in the Brazilian Osteosarcoma Treatment Group (BOTG) studies III, IV, and V. Gender, age, time from onset of symptoms to diagnosis, primary tumor site, presence or absence of metastases at diagnosis, tumor size, type of surgery (limb-sparing or amputation), treatment protocol, and histological response were correlated with survival.
Results: The estimated 5-year overall survival and event-free survival (EFS) rates for the 553 eligible patients were 49% and 39% respectively; of the 390 non-metastatic patients included in the total, overall- and event-free survival were 59% and 48% respectively. Metastases at diagnosis, primary tumor site, type of surgery, and histological response were significant predictors of overall survival and EFS in univariate and multivariate analysis, whereas tumor size and treatment protocol lost prognostic significance in multivariate analysis.
Conclusion: We report on the outcome of three consecutive studies for the treatment of osteosarcoma carried out in Brazil over 15 years. Although the survival rates presented are below those reported in current literature, it represents the result of a favorable experience gathered from the national collaborative work.