High dose rate interstitial brachytherapy in soft tissue sarcoma. Technical aspects and results

Radiation is essential for function preservation in the management of soft tissue sarcoma (STS). One of the advantages of brachytherapy is that it allows for specific localization of radiation dose to the tumor bed. We examined the results of our clinical experiences with immediate postoperative high dose rate (HDR) brachytherapy and external beam radiation treatment (EBRT) for STS. A total of 17 patients (11 primary and six recurrent) between 1995 and 1999 were included in this review. The inclusion criteria for HDR and EBRT were as follows: high-grade tumor, low-grade tumor of ≥10 cm, recurrent tumor, tumor abutting or invading critical structures and positive margin. The catheters (six French) were placed parallel to the long axis of the tumor with a 1-1.5 cm spacing in between. If necessary, muscle or gel-foam was placed over the critical structures to maintain a minimum space of 0.5 cm from the catheters. On postoperative day 6, patients received HDR (2-3 Gy/fraction x 6, twice daily). Three weeks later, patients received EBRT (total 36-60 Gy). The follow-up duration was between 13 and 60 months (median 31 months). There was no local failure within the radiation field in any of the patients. One patient required wound revision for delayed healing after brachytherapy. During EBRT, most patients experienced only mild erythema (grade 1 or 2 skin reaction). In long-term follow-up, there were no patients with neuropathy or significant fibrosis. Our results suggest that immediate postoperative HDR with a total dose of 12-18 Gy over 3 days is an effective treatment combined with EBRT in the management of STS. (author)