Focal salvage high-dose-rate brachytherapy with implantable rectum spacer for locally recurrent prostate cancer after initial low-dose-rate with grade 3 rectal toxicity

Purpose: Locally recurrent prostate cancer after previous radiation therapy remains challenging. One of the cura-tive options for these patients is salvage brachytherapy. There are no reports available on the use of a biodegradable rectal balloon implantation (RBI) in combination with brachytherapy in patients with recurrent prostate cancer after previous radiotherapy.Case presentation: Here, we report on a patient with a local recurrence at five years after previous low-dose-rate brachytherapy with a prescribed dose of 145 Gray (Gy) for a low-risk prostate adenocarcinoma. The patient experi-enced grade 3 rectal toxicity, which was resolved at the time of local recurrence. He was treated with focal high-dose-rate (HDR) brachytherapy of 2 fr. x 13 Gy after RBI implantation. Four years post-salvage treatment, there was no evidence of biochemical recurrence according Phoenix definition, and no gastro-intestinal or genitourinary toxicity.Conclusions: This case describes the use of RBI implantation in combination with a focal salvage HDR in a patient with recurrent disease, with significant initial grade 3 rectal toxicity after previous irradiation. The use of a biodegrad-able RBI proved to be a promising solution for such a patient; however, this method needs to be further investigated.