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

In Cancer this week:

An analysis from Dr Alektiar at MSKCC retrospectively examines their experience with IMRT treating STS (soft tissue sarcoma), compared to a historical cohort of brachytherapy patients. Of course there are significant limitations in any retrospective analysis, but the local control was quite good with IMRT, with no significant difference in toxicity. Obviously one would prefer randomized data before accepting a new modality as standard of care, however, given the overall rarity of STS, and the broad acceptance of EBRT, it seems likely that this will be the treatment of choice moving forward.

Link and Abstract:

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

Abstract

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. Cancer 2011. © 2011 American Cancer Society.

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