LOCAL-CONTROL AND FUNCTIONAL RESULTS AFTER TWICE-DAILY RADIOTHERAPY FOR EWINGS-SARCOMA OF THE EXTREMITIES

Purpose: Radiotherapy (RT) has been the predominant local treatment fo r Ewing's sarcoma of bone at the University of Florida. Twice-daily hy perfractionated RT was initiated in 1982 to improve local control and functional outcome. This retrospective review compares the results of once-daily vs. twice-daily RT in patients with primary Ewing's sarcoma of an extremity, with emphasis on functional outcome. Methods acid Ma terials: Between June 1971 and January 1990, 37 patients were treated at the University of Florida for nonmetastatic Ewing's sarcoma of bone with a primary lesion in an extremity. Three patients underwent amput ation. Of 34 patients treated with RT, 31 had RT alone and 3 had a com bination of RT and local excision. Before 1982, 14 patients received o nce-daily RT; since 1982, 17 patients have received twice-daily RT. Do ses of once-daily RT varied from 47 to 61 Gy at 1.8-2 Gy per fraction. Doses of twice-daily RT varied, depending on the response of the soft -tissue component of the tumor to chemotherapy, and ranged from 50.4 t o 60 Gy at 1.2 Gy per fraction. Some patients in the twice-daily RT gr oup also received total body irradiation 1-3 months after local RT as part of a conditioning regimen before marrow-ablative therapy with ste m cell rescue. They received either 8 Gy in two once-daily fractions o r 12 Gy in six twice-daily fractions. The six patients who received su rgery were excluded from local control analysis. Local control rates w ere calculated using the Kaplan-Meier (actuarial) method. Fifteen pati ents had a formal functional evaluation. Results: In the 31 patients t reated with RT alone, the actuarial local control rate at 5 years was 81% for patients treated twice daily and 77% for those treated once da ily (p = NS). No posttreatment pathologic fractures occurred in patien ts treated twice daily, whereas five fractures occurred in those treat ed once daily (p = 0.01). On functional evaluation, less loss in range of motion (15 degrees vs. 28 degrees of loss, p = 0.02) and a lesser degree of muscle atrophy (8% vs. 21% loss in muscle circumference, p = 0.0004) occurred with twice-daily than with once-daily RT, A trend to ward less fibrosis and less local alopecia was seen in patients treate d twice daily. Patients treated twice daily received a higher Musculos keletal Tumor Society functional rating (determined by the Department of Orthopaedics) than those treated once daily (29.4 vs. 26.0, p = 0.1 5). Conclusions: Local control rates were similar in the two groups (7 7% vs. 81%), but functional results were superior in the group treated twice daily.