Local control and survival from the Cooperative Osteosarcoma Study Group studies of the German Society of Pediatric Oncology and the Vienna Bone Tumor Registry.

The use of aggressive chemotherapy undoubtedly has brought about a dramatic increase in the cure rate of osteosarcoma. The authors' investigations have increased the authors' knowledge of chemotherapy for osteosarcoma, the differential efficacy of currently used agents, and the pronounced schedule dependency and relative route independency of their efficiency. The authors were able to confirm the prognostic significance of tumor response after preoperative chemotherapy. Preoperative chemotherapy in itself has facilitated and promoted limb-salvage surgery. Also, more patients can be cured today by use of aggressive thoracic surgery in case of primary or secondary pulmonary metastases. The authors' efforts to steadily increase metastasis-free survival rates by intensifying chemotherapy in this series of studies, however, have been only moderately successful. Still, chemotherapy-related acute toxicity is considerable and increases with aggressiveness of treatment, and the manifestations of late toxicity may continue to increase with follow-up time. Future trials should be targeted toward exploration of the minimum indispensable amount of toxic treatment yielding comparable or even better results than those currently attainable.