OSTEOSARCOMA OF THE TRUNK TREATED BY MULTIMODAL THERAPY - EXPERIENCE OF THE COOPERATIVE OSTEOSARCOMA STUDY-GROUP (COSS)

The case histories of all patients with osteosarcoma of the trunk ente red into the consecutive studies COSS 80 through COSS 86 of the Cooper ative German/Austrian Osteosarcoma Study Group (COSS) were analyzed in order to evaluate their clinical characteristics and the impact of mo dern neoadjuvant therapy on prognosis. They were compared to those of all patients with extremity osteosarcoma treated according to the same protocols. While tumors of the trunk comprised only 32 (4.8%) of 665 primary classical osteosarcomas, secondary osterosarcomas were much mo re likely to be located in bones of the axial skeleton (6 of 18, 33%). Patients with primary osteosarcoma of the axial skeleton were older ( mean: 20.8 vs. 15.2 years, P < 0.01) and were more likely to present w ith metastases at diagnosis (34% vs 12%, P < 0.001) than those with pr imary extremity osteosarcoma. In contrast to extremity tumors, local s urgical treatment failure was very common in osteosarcomas of the trun k. Complete tumor removal was achieved in less than half of all evalua ble cases. The prognosis of eight patients with localized primary axia l osteosarcoma and effective surgical local control was not inferior t o that of 483 equally evaluable patients with extremity tumors. In con clusion, while secondary systemic spread of axial osteosarcoma may be avoided in patients treated with multiagent chemotherapy, successful t reatment is often barred by primary metastatic disease and inability t o control the local tumor site. (C) Wiley-Liss, Inc.