SYNCHRONOUS MULTIFOCAL OSTEOSARCOMA - RESULTS IN 12 PATIENTS TREATED WITH NEOADJUVANT CHEMOTHERAPY AND SIMULTANEOUS RESECTION OF ALL INVOLVED BONES

Background: Multifocal osteosarcoma is a rare type of tumor which is a lways excluded from therapy trials and is therefore rarely investigate d for prognosis and treatment. Patients and methods: Twelve patients w ith synchronous multifocal osteosarcoma underwent neoadjuvant chemothe rapy and, when feasible, simultaneous resection of involved bones. Res ults: Four patients were unsuitable for resection and died 5-13 months (average 9 months) later. In eight patients all lesions were resected simultaneously. Four patients are disease-free at 15, 20, 24, and 60 months (average 29 months), and four relapsed and died at 12, 24, 30 a nd 36 months (average 30.5 months). Conclusions: Chemotherapy associat ed with aggressive surgery may be useful. The histological response of different lesions in the same patient are strongly correlated, confir ming that synchronous multifocal osteosarcoma is not originally multic entric but unicentric with bone metastases.