Interstitial brachytherapy in soft tissue sarcomas: The Rambam experience

Background: There are radiobiologic and technical advantages to the use of interstitial brachytherapy alone or as an adjunct to external beam radiotherapy in the postoperative treatment of soft tissue sarcomas. Objectives: To review the experience of the Rambam Medical Center in implementing interstitial brachytherapy in the treatment of 32 patients with soft tissue sarcomas. Methods: Thirty-two patients with variously located soft tissue sarcomas were managed with a combination of surgery and brachytherapy of the tumor bed, with or without EBRT. In 27 of 32 patients, brachytherapy catheters were placed intraoperatively, while in 5 patients the implant was performed as a separate postoperative procedure. Twenty-seven patients received low dose-rate brachytherapy with Iridium-192 seeds. Five patients received fractionated high dose-rate brachytherapy using the microSetectron machine. Results: With a median follow-up of 36 months, the overall local control rate was 87.5%. Four of 32 patients (13%) failed locally at the implant site, and 6 (19%) developed lung metastasis. Two of the five patients with lung metastasis had a local recurrence as well. At the time of analysis, eight patients had died of sarcoma (disease-specific mortality rate was 25%), while three had died of intercurrent causes. The 5 year actuarial disease-free survival rate was 56%, and the 5 year actuarial overall survival 70%. Five patients (16%) developed severe wound complications following surgery/brachytherapy, and six patients (19%) developed late local toxicity (fibrosis and telangiectasia). Conclusions: Wide local excision followed by interstitial brachytherapy has resulted in an 87.5% local control rate with a 16% local complication rate.