Low-dose neoadjuvant external beam radiation therapy for soft tissue sarcoma

For soft tissue sarcoma, neoadjuvant external beam radiation therapy (EBRT) to 50 Gy has the same local control (LC) and overall survival as postoperative radiation therapy (PORT) to 60 Gy, but with increased wound complications. We examined whether low-dose neoadjuvant EBRT would decrease acute toxicity while maintaining LC.

From 1971 to 2008, 1,765 patients with nonmetastatic soft tissue sarcoma were treated with radiation therapy at Massachusetts General Hospital. We identified 42 patients treated with low-dose neoadjuvant EBRT (median, 20 Gy; range, 16-26) followed by surgical resection and PORT. PORT included EBRT (25 patients; median, 40 Gy; range, 20-56.2), brachytherapy (13 patients; median, 42 Gy; range, 26-50), and intraoperative radiation therapy (IORT) (4 patients; median, 12.5 Gy; range, 8-20). The median total dose was 63.3 Gy (range, 28-78.4).

Median follow-up was 36 months (range, 4-318). Severe acute wound complications were reported in 15 patients (36%) and correlated to PORT technique (16% EBRT, 69% brachytherapy, 50% IORT, p = 0.004). The 5-year LC was 73% and correlated to PORT technique (68% EBRT, 100% brachytherapy, 50% IORT, p = 0.03) and histology (p = 0.05), with a trend to improvement if >60 Gy (p = 0.10). The 5-year overall survival was 65% and correlated to extent of resection (p < 0.001) and margin status (p < 0.001).

Despite using low-dose neoadjuvant EBRT, we report a high rate of severe acute wound complications that was strongly associated with brachytherapy. Modification of the brachytherapy technique may decrease acute toxicity while maintaining excellent local control. Further study must be conducted before recommending broader application.