Characterization of localized osteosarcoma of the extremity in children, adolescents, and young adults from a single institution in South Texas.

Background: Osteosarcoma is the most common bone malignancy in children, adolescents, and young adults. Most study cohorts have 10% to 15% Hispanic patients that encompass many different Hispanic backgrounds. This study characterizes the effect of mainly Mexican American ethnicity on the outcome of children, adolescents, and young adults with osteosarcoma. Methods: A retrospective analysis of demographics, tumor characteristics, response to treatment, and survival outcome of all localized osteosarcoma of the extremity patients below 30 years of age was performed. A Kaplan-Meier estimates with log-rank tests and Cox proportional hazard regression models were used. Results: Fifty patients (median age, 15; range, 2 to 28 y) with localized high-grade osteosarcoma of the extremity were diagnosed between January 2000 and December 2010. The cohort was 70% Mexican Americans. With a median follow-up of 39 months (range, 5 to 142 mo), patients had a 5-year overall survival and event-free survival of 65% and 48%, respectively. We observed a significantly decreased 5-year event-free survival in patients diagnosed before age 12 relative to patients diagnosed between ages 12 and 29 (11% vs. 57%, P < 0.001). We also found that tumor necrosis was not predictive of outcome in our patients. Conclusions: The preadolescent patients of predominately Mexican American ethnicity had an increased rate of relapse when compared with previous studies. Tumor necrosis is not directly predictive of outcome in this population.