The role of radiation therapy in the management of non-metastatic Ewing's Sarcoma of bone. Report of the intergroup Ewing's Sarcoma Study

Abstract

The role of radiation therapy in local tumor control and decreased incidence of pulmonary metastasis is reported in 271 patients who were entered into the Intergroup Ewing's Sarcoma Study with more than one year follow-up and on whom all radiotherapy records were reviewed. The majority of the patients were irradiated to the primary tumor with doses of 4500 to 6500 rad in five to six weeks in combination with systemic administration of three drugs (vincristine, actinomycin-D and cyclophosphamide) or four drugs (vincristine, actinomycin-D, cyclophosphamide and adriamycin). One of the groups of patients was treated with three drugs and bilateral pulmonary irradiation (1500 rad, uncorrected dose, in two weeks). Preliminary analysis shows an overall local primary tumor control of 89 %. Patients with lesions in the pelvis had a local failure rate of 17% (9 of 52) and in the humerus 23% (7 of 31). Factors affecting local recurrences are analyzed in detail. Distant metastases have been noted in 40% of all patients; the highest proportion was noted in the pelvis (49%). There was a significant difference in the appearance of pulmonary metastases in the patients who were treated with four drugs (9.7%) and in the group who received three drugs and pulmonary irradiation (23.5%) when compared with the patients treated with three drugs only (37%). Intensive chemotherapy and radiotherapy significantly improve local tumor control and survival of patients with localized Ewing's sarcoma. However, the high incidence of metastasis suggests the need for more effective systemic chemotherapy to further improve treatment results. It is very important to determine the optimal dose of irradiation and minimal volume to be treated in order to achieve optimal survival and primary tumor control with the least sequela.