Osteosarcoma with metastasis at initial diagnosis: Current outcomes and prognostic factors in the context of a comprehensive cancer center.

The aim of this study was to report the outcomes and prognostic factors for a cohort of patients with osteosarcoma who presented with metastasis at initial diagnosis. Data of consecutive patients with osteosarcoma and metastatic disease at initial presentation, who were treated and followed up at a single institution, were retrospectively reviewed. The effect of potential factors on overall survival (OS) was analyzed through univariate and multivariate analysis. Between January, 2000 and March, 2013, a total of 135 patients with osteosarcoma, of whom 21 (16.0%) had distant metastasis at initial presentation, were diagnosed and treated at our center and were included in this analysis. The patients were treated with a strategy that integrates multi-agent chemotherapy and resection of all sites of gross disease whenever feasible. The 5-year OS and event-free survival (EFS) were 23.0% and 11.0%, respectively. The factors associated with inferior OS in the univariate analysis included the osteoblastic variant, extrapulmonary metastasis and failure to achieve complete remission. In the multivariate analysis, the osteoblastic variant [hazard ratio (HR)=4.83, 95% confidence interval (CI): 1.16-20.0, P=0.038] and extrapulmonary metastasis (HR=5.0, 95% CI: 1.40-17.94, P=0.018) were the only independent prognostic factors. The current outcomes of patients with osteosarcoma and metastasis at initial diagnosis remained poor. The osteoblastic subtype and extrapulmonary metastatic sites predicted poor survival in our series. To the best of our knowledge, this is the first report of the correlation between the histological subtype and survival for patients with metastatic disease at initial presentation; therefore, confirmation in future studies is required.