NEOADJUVANT CHEMOTHERAPY IN MALIGNANT FIBROUS HISTIOCYTOMA OF BONE AND IN OSTEOSARCOMA LOCATED IN THE EXTREMITIES - ANALOGIES AND DIFFERENCES BETWEEN THE 2 TUMORS

Background. Malignant fibrous histiocytoma (MFH) is a rare bone tumor usually treated like osteosarcoma. Studies on analogies and difference s between the two tumors have seldom been reported. Patients and metho ds: Between March 1982 and December 1994, 51 patients with high-grade MFH of bone and 390 with high-grade osteosarcoma were treated with the same regimen of neoadjuvant chemotherapy. All of the tumors in both g roups were located in the limbs. Preoperative chemotherapy was perform ed according to three different, successively activated, regimens cons isting of MTX/CDP intraarterially, MTX/CDP/ ADM, and MTX/CDP/ADM//IFO. Results: The rate of limb salvage was the same in both the MFH (92%) and osteosarcoma (85%) patients. MFH showed a statistically significan tly lower rate of good histologic response, 90% or more tumor necrosis (27% vs. 67%, P = 0.00001) for all three regimens. Despite this low c hemosensitivity, the disease-free survivals of the two neoplasms were similar (67% vs. 65%). Conclusions: In terms of histologic response to primary chemotherapy, MFH has a lower chemosensitivity than osteosarc oma. Nevertheless, the two tumors have similar prognoses when treated with chemotherapy regimens based on MTX, CDP, ADM and IFO.