Neoadjuvant chemotherapy for osteosarcoma of the extremity: intensification of preoperative treatment does not increase the rate of good histologic response to the primary tumor or improve the final outcome.

PURPOSE: The aim of this study was to compare the results in terms of histologic response to primary chemotherapy of two sequential studies in osteosarcoma patients preoperatively treated with methotrexate, doxorubicin, cisplatin, and ifosfamide, given at different doses. PATIENTS AND METHODS: Between January 1993 and March 1995, 171 patients with osteosarcoma of the extremity were treated according to a protocol of neoadjuvant chemotherapy with preoperative methotrexate, cisplatin, doxorubicin, and ifosfamide. From April 1995 to December 1999, 196 osteosarcoma patients were preoperatively treated with the same drugs at higher doses. Postoperatively, patients received the same treatment in both studies used, but poor responders (tumor necrosis <95%) had more cycles of treatment than good responders.
RESULTS: Comparing the two chemotherapy regimens, there were no significant differences in terms of good histologic response to chemotherapy (69% vs. 62%), 5-year event-free survival (60% vs. 65%), 5-year overall survival (74% vs. 80%), and rate of local recurrence (6% vs. 4%). The 5-year event-free survival was significantly related to the serum level of alkaline phosphatase before treatment (77% for patients with normal values vs. 46% for patients with high values) and the degree of histologic response to preoperative chemotherapy (69% for good responders vs. 54% for poor responders).
CONCLUSIONS: Increasing the doses of preoperative chemotherapy does not improve the rate of good histologic response and survival in osteosarcoma of the extremity. The degree of necrosis induced by preoperative treatment probably reflects an innate sensitivity to chemotherapy, which is not altered by increasing drug doses.