Implantable Rectal Spacers in Prostate Cancer Radiation Therapy: A Systematic Review

This systematic review provides an overview of the available literature regarding the efficacy and safety of implantable rectal spacers (IRSs) in reducing rectal dose and gastrointestinal toxicity during prostate cancer radiation therapy.

A comprehensive literature search was conducted in December 2024. Results included prospective research in humans and were limited to the English language. The 30 included studies, all published between 2007 and 2024, were randomized controlled trials or clinical trials that focused on adverse events, rectal dose reduction, gastrointestinal toxicity, or bowel quality of life. Next, IRS implantation technique, safety, and spacing distance were assessed.

Randomized controlled trial data were available for hydrogel, hyaluronic acid, and rectal balloon implant spacers, whereas only one pilot study is available for human collagen. Prospective clinical research on IRS in brachytherapy is limited. One centimeter of spacing between the rectum and prostate sufficed to spare the rectum, the primary dose-limiting organ. Findings indicate a favorable safety profile, with an overall complication rate of 0,96% when using hydrogel spacers. There was no grade 4 to 5 gastrointestinal toxicity reported in clinical trials. The use of an IRS was associated with improved long-term bowel quality of life.

The integration of IRS into clinical practice offers the potential to enhance the therapeutic landscape for patients with prostate cancer. However, its use should be guided by careful consideration of individual patient needs to determine those who benefit most from the IRS because not all patients may benefit equally.