[Criteria for the evaluating treatment on primary bone sarcoma]

The criteria for the evaluation of the treatment on primary bone sarcoma proposed by the Musculoskeletal Tumor Committee of the Japanese Orthopaedic Association (JOA) were accepted in 1993 by the Joint Committee for Cancer Therapy of the Japan Society for Cancer Therapy. The responses to treatment are classified as a complete response (CR), a partial response (PR), no change (NC), or as progressive disease (PD). It is a requirement that the condition of CR, PR, or NC continues for at least 4 weeks. The radiographical criteria are as follows: CR, the disappearance of the intramedullary lesions and the bone trabeculae recovering a normal appearance; PR, the circumscription of the extraosseous tumor and an appearance of sclerotic foci within the intramedullary lesion; NC, no changes noted in the extraosseous and intramedullary lesions; PD, an increase in the extraosseous or intramedullary lesion and/or the appearance of new lesions. Histopathological criteria are as follows: CR, no tumor cells appearing viable in any of the histologic sections; PR, greater than 90% tumor necrosis attributable to treatment; NC, 50 to 90% tumor necrosis and other secondary changes attributable to treatment; PD, less than 50% tumor necrosis. Responses in the clinical signs and symptoms including tumor size (or circumference of the extremities at the site of the tumor), pain and local heat are also graded as follows: PR, subsiding symptoms and/or decrease in the tumor size; NC, neither exacerbation nor decrease in the symptoms and no change in size; PD, the exacerbation of symptoms or an increase in size. Additionally, the serum alkaline phosphatase level can be used for evaluating the effect of the treatment on the osteosarcoma. The extent of the response to preoperative chemotherapy is a powerful predictor of patient survival.