With the intention of starting an international protocol between Italy and Scandinavia on neoadjuvant treatment of extremity osteosarcoma using the four active drugs at maximum doses (doxorubicin 75 mg/m2 pre-operatively, and 90 mg/m2 post-operatively, cisplatin 120 mg/m2, methotrexate 12 g/m2, and ifosfamide 15 g/m2), a single center (the Rizzoli institute) performed a pilot study to closely monitor toxicity, safety, and tumor necrosis. Only 7 patients (10%) had a reduced number of the scheduled cycles. A total of 1,050 of the expected 1,076 cycles (98%) were administered. Delays and dose reduction were minimal, leading to a mean received dose intensity of 89%. Limb salvage surgery was performed in 59 cases (87%), with 6 amputations and 3 rotation plasties. Chemotherapy-induced necrosis higher than 95% was observed in 38 patients (56%). Eleven patients had total necrosis (16%). At a median follow-up of 60 months (range 50-65 months), 53 patients (73%) were continuously disease-free. Six of the relapsed patients were rescued with further treatments leading to an overall survival of 87%. Hematological toxicity was remarkable despite the use of G-CSF and hospitalization due to febrile neutropenia occurred in 25 patients (37%). Platelet transfusions were required in 77 of the 194 episodes of grade 4 thrombocytopenia, but no case of major bleeding was observed. Red blood cell transfusions were necessary in all patients (in 15 cases perioperatively only). Non-hematological toxicity comprised grade 1-2 nephrotoxicity in 3 cases, CNS toxicity in 2 cases, and dilata- tive cardiopathy leading to heart transplantation in 1 case. In conclusion, the pilot study was feasible in the vast majority of cases with toxicity not superior to that of the previous protocols where chemotherapy was given in lower doses. The rate of limb salvage procedures, event-free survival and overall survival seemed to be higher than in previous protocols. On the basis of this study, in March 1997 the Italian and Scandinavian Sarcoma Groups started a new protocol for osteosarcoma of the extremities.