Extremity osteosarcoma in childhood: Prognostic value of radiologic imaging

PURPOSE: To evaluate previously described radiologic prognostic factors in extremity osteosarcoma. MATERIALS AND METHODS: In 47 pediatric patients, available images were evaluated for seven prognostic factors at diagnosis and seven additional factors after preoperative chemotherapy. These factors were correlated with histopathologic response and clinical outcome. The association of histopathologic response and outcome was also evaluated. RESULTS: Metastases at presentation and a >20-cm-diameter soft-tissue mass were predictive of a poor outcome but occurred in few patients. Factors most predictive of <90% tumor necrosis after chemotherapy included an increase or no change in soft-tissue mass size and increased bone destruction. Although a significant relationship (P < .05) was found between histopathologic response and outcome, no factors predictive of histopathologic response were also predictive of outcome. The accuracy of pathologic response in predicting outcome was 66%. CONCLUSION: Radiologic studies are of only limited use in predicting which patients with extremity osteosarcoma will have a poor response to chemotherapy or a poor outcome, and are not useful in predicting a good response or outcome.