Impact of intensity-modulated radiation therapy on local control in primary soft-tissue sarcoma of the extremity

Purpose One of the concerns about intensity-modulated radiation therapy (IMRT) is that its tight dose distribution, an advantage in reducing RT morbidity to surrounding normal structures, might compromise tumor coverage. The purpose of this study is to determine if such concern is warranted in soft-tissue sarcoma (STS) of the extremity. Methods Between 02/02 and 05/05, 41 adult patients with primary STS of the extremity were treated with limb-sparing surgery and adjuvant IMRT. The margins were positive/within 1 mm in 21. Tumor size was more than 10 cm in 68% of patients and grade was high in 83%. Preoperative IMRT was given to 7 patients (50 Gy) and postoperative IMRT (median dose, 63 Gy) was given to 34 patients. Complete gross resection including periosteal stripping/bone resection was required in 11, and neurolysis/nerve resection in 24. Results With a median follow-up time of 35 months, two (4.8%) of 41 patients developed local recurrence. The 5-year actuarial local control rate was 94% (95% CI, 86% to 100%). The local control rate was also 94% for patients with negative or positive/close margin. Other prognostic factors such as age, size, and grade did not impact local control either. The 5-year distant control rate was 61% (95% CI, 45% to 76%) and the overall survival rate was 64% (95% CI, 45% to 84%). Conclusion IMRT in STS of the extremity provides excellent local control in a group of patients with high risk features. This suggests that the precision with which IMRT dose is distributed has a beneficiary effect in sparing normal tissue and improving local control.