Diagnosis and tumor response in osteosarcoma and Ewing's sarcoma, according to treatment protocols SSG II, SSG VIII, ISG/SSG I, SSG IV and SSG IX.

114 patients with osteosarcoma in the extremities had been reported to the SSG II trial, 132 to the SSG VIII trial and, until October 1998, 99 to the ISG/SSG I trial. The SSG IV trial included 53 patients and the SSG IX trial 104 patients until October 1998. In the SSG II trial, 19% were good responders (grades III and IV) as compared to 51% in the SSG VIII trial. On reevaluation was the response changed in one forth of the cases in both the SSG II and SSG VIII trials. In 9 and 10 cases (8%), respectively, the reevaluation resulted in a change from "good responder" to "bad responder". In the ISG/SSG I trial, the preliminary results showed a good response in 22% of the cases. In the SSG IV trial, 44% were good responders (grades III and IV), as compared to 54% in the SSG IX trial.