Perioperative Hyperfractionated High-Dose Rate Brachytherapy Combined with External Beam Radiotherapy in the Treatment of Soft Tissue Sarcomas

Abstract

Low-dose rate brachytherapy alone or in combination with external beam radiotherapy represents a well-established adjuvant treatment in soft tissue sarcomas following surgical resection. The experience with high-dose radiotherapy in this indication is limited. The purpose of our study was an evaluation of the viability of perioperative hyperfractionated high-dose rate brachytherapy in combination with external beam radiotherapy for primary and recurrent soft tissue sarcomas. From February 1998 through June 2002, 10 adult patients with soft tissue sarcomas were treated by interstitial perioperative high-dose rate brachytherapy and external beam radiotherapy. TNM classification was pT2bpN0pM0 in 9 patients and pT1bpN0pM0 in 1 patient. Grade of differentiation was G1 (2 patients), G2 (n = 1), G3 (n = 5), G4 (n = 2). Surgical margins were negative in 7 cases, close in 2 cases and positive in 1 case. The tumor was localized in an extremity in all cases. Hyperfractionation 3 Gy twice daily at 10 mm from the plane of sources was used for brachytherapy, with total doses 18-30 Gy. The patients received external beam radiotherapy with doses 40-50 Gy after brachytherapy. Follow-up periods were between 24-71 months (median, 46). Local control of the disease was achieved in all 10 patients. Distant metastases occurred in 2 cases. One patient was disease free after salvage surgery and chemotherapy, and one patient died of lung disease progression 14 months after brachytherapy. In one case, subcutaneous fistula occurred after radiotherapy and was cured by an excision. Six patients experienced grade 1 or 2 fibrosis and 1 case a mild peripheral neuropathy was recorded. Our study on a small number of patients suggests that perioperative hyperfractionated high-dose rate brachytherapy with doses 8 x 3 Gy in combination with external beam radiotherapy 40-50 Gy is a promising method to achieve high biological doses in the postoperative radiotherapy of soft tissue sarcomas without severe late morbidity and warrants further research.