Synchronous multifocal osteosarcoma: results in twelve patients treated with neoadjuvant chemotherapy and simultaneous resection of all involved bones.

BACKGROUND Multifocal osteosarcoma is a rare type of tumor which is always excluded from therapy trials and is therefore rarely investigated for prognosis and treatment. PATIENTS AND METHODS Twelve patients with synchronous multifocal osteosarcoma underwent neoadjuvant chemotherapy and, when feasible, simultaneous resection of involved bones. RESULTS 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 and 36 months (average 30.5 months). CONCLUSIONS Chemotherapy associated with aggressive surgery may be useful. The histological response of different lesions in the same patient are strongly correlated, confirming that synchronous multifocal osteosarcoma is not originally multicentric but unicentric with bone metastases.