Analysis of local tumor control in ewing's sarcoma.Preliminary results of a cooperative intergroup study

Abstract

This report is a preliminary analysis of the local tumor control in 187 patients treated with multi-agent chemotherapy and local radiation therapy for non-metastatic Ewing's sarcoma. Patients were treated according to three different regimens, all of which included irradiation of the primary tumor and involved bone (5000-6000 rads in 5-6 weeks). The first group was treated with a combination of cyclophosphamide, vincristine, adriamycin and actinomycin-D. The second group received cyclophosphamide, vincristine and actinomycin-D. The third group was treated with cyclophosphamide, vincristine and actinomycin-D in addition to bilateral pulmonary irradiation. The present results, after a median follow-up of 24-30 months in the various groups combined, indicate that the local control is 87%. Twenty-two of 25 local failures appeared within 24 months (88% of recurrences). No difference in time of appearance of local recurrence was noted in the three treatment regimens. The highest incidence of local recurrence has been noted in the humerus (22%), the pelvis (19%), the tibia (14%) and the femur (11%). Sixty-seven of the 187 patients (35.8%) have developed distant metastases, mostly to the lungs and to other skeletal sites. Of the patients with pelvic primaries, 62% have developed distant metastases followed by the humerus (41%), the femur (36%) and the tibia (24%). A detailed analysis of radiation therapy technical factors was done in 110 patients with complete dosimetry data at the time of this report. There is a trend indicating that patients who received doses over 6000 rads (20/20) or with lower doses combined with chemotherapy containing adriamycin (9/9) have a higher local control. However, the difference with the other groups (67/81-83%) was not statistically significant. Radiation therapy in combination with multiple chemotherapy is an effective treatment method to control Ewing's sarcoma locally. The late effects of this intensive combined therapy must be assessed in long term survivals. Future studies in Ewing's sarcoma should attempt to elucidate crucial issues such as the optimal volume of bone that should be irradiated, the potential value of limited surgical resection of gross tumor and the determination of optimal multi-agent regimens which will enhance local tumor control and diminish distant metastases. Because of the rarity of this tumor, the need for cooperative controlled clinical trials is emphasized. Cancer 40:2864-2873, 1977.