Rectourethral fistula after perirectal spacer placement requiring pelvic exenteration.

Despite the widespread use of perirectal spacers to reduce radiation-induced rectal toxicity during prostate cancer treatment, postmarketing data reveal rare but significant complications. This case report details a severe complication of rectourethral fistula necessitating robotic pelvic exenteration with urinary and faecal diversion following perirectal spacer placement. Although SpaceOAR has been shown to reduce rectal radiation dose, the ensuing clinical benefit remains inconclusive in real-world data. Our findings underscore the need for thorough patient counselling regarding the risks and benefits of spacer use, particularly given the lack of evidence for improved cancer control or gastrointestinal toxicity. We further review the literature to highlight the importance of physician technique during placement and the potential avenues for early identification and management of complications. Future research must aim to better characterise real-world risks and develop strategies for mitigating severe outcomes.