Feasibility of balloon rectal spacer implantation in HDR and LDR brachytherapy for prostate cancer treatment.

Purpose: This study evaluates the use of a biodegradable balloon rectal spacer in two prostate cancer patients undergoing low dose radiation (LDR) and salvage high dose radiation (HDR) brachytherapy. The spacer aims to reduce radiation dose to adjacent organs, particularly the rectum, in patients previously treated with radiation.

Methods: The balloon spacer was implanted transperineally under transrectal ultrasonography (TRUS) guidance in two patients. For the LDR case (73-year-old, intermediate-risk), the balloon was placed postimplant with 55 iodine-125 seeds delivering 145 Gy. For the HDR case (66-year-old, high-risk), the balloon was placed one week before treatment, which delivered 23 Gy in two weekly fractions using 16 channels.

Results: The balloon provided a 14-15mm separation between rectum and prostate. In the LDR case, prostate D90 was 149.1Gy (102.83%), V100 was 91.95%, and rectum D30 was 23.93Gy (16.50%). For the HDR case, prostate D90 was 11.63Gy (105.79%), V100 was 93.63%, and rectum D0.5cc was 8.04Gy (73.15%). Both patients tolerated the treatment well, with no observed postoperative complications at 6-month follow-up.

Conclusions: The use of a rectal balloon spacer in both salvage HDR and LDR brachytherapy is feasible and safe, allowing for controlled placement and providing rectal protection from high radiation doses.