HIGH-DOSE HYPERFRACTIONATED RADIOTHERAPY IN THE TREATMENT OF EXTREMITY SOFT-TISSUE SARCOMAS

A hyperfractionated radiotherapy schedule has been evaluated in the treatment of 29 adults with limb or limb girdle soft tissue sarcomas. The objective was to increase the total administered dose and possibly improve local control, without increasing late normal tissue damage. Twice daily 1.25 Gy fractions (with a minimum interval of 6 h) have been given over 5 to 6 weeks to 12 patients pre-operatively, 10 post-operatively and 7 palliatively. Five patients received 62.5 Gy in 5 weeks pre-operatively and 3 palliatively. Nineteen of the remaining 21 patients received 75 Gy in 6 weeks with a field size reduction after 5 weeks. Sixteen of 29 tumours were situated in the thigh and only 2 were in the upper limb. Twenty were of high grade. The mean tumour size of those treated radically was 13.1 cm (range 5 to 40 cm). Sixteen patients (76%) given 75 Gy developed moderate or severe skin erythema maximal at 5 weeks. Despite the large field sizes used (mean phase one of 34.5 cm, and phase two of 22.8 cm) only 2 patients failed to complete the planned treatment because of the severity of these reactions. Two other patients developed partial wound breakdowns after the end of treatment - both healing spontaneously. Fourteen patients developed an area of moist desquamation - 11 mild, 2 moderate and one severe. There have been four late wound breakdowns requiring surgical intervention; all have since healed well. The median follow up is short at 556 days. Ten of 19 evaluable patients have developed moderate/severe induration, 5/19 mild and 4/19 none. There has been one local failure associated with regional node involvement and lung metastases. Although it was feasible to deliver the planned very high doses to these patients by the use of hyperfractionation, early results suggest that the late damage caused by this regime is greater than that from standard once daily 2 Gy fractionation to a total dose of 60 Gy in 6 weeks. A lower dose per fraction is now being evaluated.