Fractionated perioperative high dose rate brachytherapy using a tissue equivalent bendy applicator

Intraoperative radiation techniques allow an additional local dose in areas at high-risk for local failure. With brachytherapy techniques, perioperative radiation can be fractionated. Fractionated treatment might offer an interesting alternative to a single dose, both to increase the therapeutic ratio and to protect late reacting tissues at risk. The dose distribution for brachytherapy applicators can be optimized using spacer materials. In this prospective study a new tissue equivalent bendy applicator (TEBA) that can remain in situ for several days is introduced, and the feasibility of fractionated perioperative high dose rate (HDR) brachytherapy is examined. 31 patients with different tumours (soft tissue sarcoma, Ewings sarcoma, rectal cancer, and locally infiltrating diseases) were treated. The TEBA was applied, depending on resection status and intraoperative findings. Planning was based on digitized radiographs and CT scans. Perioperative HDR brachytherapy was performed using an individual treatment schedule. In 29 patients perioperative radiation was given and in 26 cases fractionated brachytherapy application was possible. TEBA application time varied from 1 day to 11 days. During this time between 1 and 8 fractions were given with total doses from 10 Gy to 25 Gy. Fractionated perioperative brachytherapy with this technique is feasible and adequate. Further studies will show whether fractionated perioperative treatment using the TEBA technique fulfils its theoretical advantages over single dose intraoperative radiotherapy by decreased late toxicity and increased local tumour control.