The patients were treated with surgical resection and perioperative high-dose-rate brachytherapy (16 or 24 Gy) for negative and close/microscopically positive resection margins, respectively. External beam radiotherapy (45 Gy) was added postoperatively to reach a 2-Gy equivalent dose of 62.9 and 72.3 Gy, respectively. Adjuvant chemotherapy with ifosfamide and doxorubicin was given to patients with advanced high-grade tumors.
Grade 3 toxic events were observed in 18 patients (30 % ) and Grade 4 events in 6 patients (10 % ). No Grade 5 events were observed. A location in the lower limb was significant for Grade 3 or greater toxic events on multivariate analysis (p?= .013), and the tissue volume encompassed by the 150 % isodose line showed a trend toward statistical significance (p?= .086). The local control, locoregional control, and distant control rate at 9 years was 77.4 % , 69.5 % , and 63.8 % , respectively. On multivariate analysis, microscopically involved margins correlated with local control (p?= .036) and locoregional control (p?= .007) and tumor size correlated with distant metastases (p?= .004). The 9-year disease-free survival and overall survival rate was 47.0 % and 61.5 % , respectively. Multivariate analysis showed poorer disease-free survival rates for patients with tumors >6 cm (p?= .005) and microscopically involved margins (p?= .043), and overall survival rates decreased with increasing tumor size (p?= .011).
Grade 3 or greater wound complications can probably be decreased using meticulous treatment planning to decrease the tissue volume encompassed by the 150 % isodose line, especially in lower limb locations. Microscopically involved margins remain a predictor of local and locoregional failure, despite radiation doses >70 Gy. Patients with tumors ? cm and microscopically involved margins are at high risk of treatment failure and death from the development of distant metastases.