Armstrong N, Bahl A, Pinkawa M, et al. - Researchers assessed the link between SpaceOAR (OAR = organs at risk) [SpaceOAR is an absorbable polyethylene glycol hydrogel spacer that is injected into the perirectal space to temporarily position the anterior rectal wall away from the prostate during radiotherapy] and radiation dosing, toxicity and quality-of-life compared with no spacer across all radiotherapy modalities for prostate cancer. They explored Cochrane Central Register of Controlled Trials, MEDLINE, and Embase in order to find the relevant studies. This analysis involved 19 studies with 3,622 patients (only one randomised controlled trial, in image-guided intensity-modulated radiotherapy (IG-IMRT), 18 comparative non-randomised controlled trials in external-beam radiotherapy, brachytherapy and combinations thereof). As shown by the randomised controlled trial in IG-IMRT, SpaceOAR not only brought about decreases in rectal radiation dose and late gastrointestinal and genitourinary toxicities, but also resulted in urinary, bowel and sexual quality-of-life improvement. These benefits were confirmed in observational studies in several radiotherapy types. There is a need for further investigation in hypofractionation.