Local control comparison of adjuvant brachytherapy to intensity-modulated radiotherapy in primary high-grade sarcoma of the extremity.

BACKGROUND: Based on results of a prospective randomized trial, brachytherapy (BRT) had been the preferred form of adjuvant radiotherapy for patients with high-grade extremity soft tissue sarcoma (STS) at our institution. In recent years, intensity-modulated radiotherapy IMRT had been increasingly used. This study compared local control by IMRT versus by BRT in primary-extremity STS.

METHODS: Between January 1995 and December 2006, 134 adult patients with high-grade primary nonmetastatic STS of the extremity were treated at this institution with limb-sparing surgery and adjuvant radiotherapy (RT). Low-dose-rate BRT was given to 71 patients between January 1995 and November 2003 to a median dose of 45 Gray (Gy). IMRT was given between February 2002 and December 2006: preoperatively to 10 (50 Gy) and postoperatively to 53 (median, 63 Gy). Median follow-up was 46 months.

RESULTS: Treatment groups were comparable in terms of gender, age, site, depth, histology (malignant fibrous histiocytoma vs other), and use of adjuvant chemotherapy. More IMRT patients had positive/close margins (<1 mm), large tumors (>10 cm), and bone or nerve stripping/resection (P = 0.006, 0.005, 0.02, and 0.002, respectively). Median follow-up was 46 months for IMRT and 47 months for BRT. Five-year local control was 92% (95% confidence interval [CI], 85-100) for IMRT versus 81% (95% CI, 71-90) for BRT, P = 0.04. On multivariate analysis, IMRT was the only predictor of improved local control, P = 0.04.

CONCLUSIONS: Local control with IMRT was significantly better than BRT despite higher rates of adverse features for IMRT in this nonrandomized comparison. IMRT should be further examined as the treatment of choice for primary high-grade extremity sarcoma.