Give him space.

Top Line: While rectal spacers make sense in theory, it’s also sure to elicit a grimace from your patient when explaining—and delivering—its placement.

The Study: So is it really worth it..? This Boston Scientific (read: proprietor of SpaceOAR)-funded meta-analysis aims to demonstrate the realized clinical utility of perirectal hydrogel spacers (read: Space OAR) as an adjunct to prostate radiation. It includes 7 (1 randomized + 6 cohort) studies comprising >1K men undergoing conventional (1.8 Gy per fraction) prostate radiation with (n=486) or without (n=525) a hydrogel spacer. The primary endpoints were not only rectal dosimetry but also bowel-related quality of life (QoL) and clinical toxicity. As anticipated, the mean volume of rectum receiving ≥70 Gy was significantly reduced with a spacer from >10% → >3%. More importantly, rates of early grade 2+ rectal toxicities were the same at ~4%, but late grade 2+ toxicities were statistically improved with a spacer from <6% → <2%. Similarly, early negative impacts (at 3 months) in bowel-related QoL were almost identical, but late impacts (at a median of 4 years) were “clinically-significantly” better with a spacer in the two studies that reported it. While this is all something, we’re left wondering: who’s delivering >40 fractions of radiation to the prostate anymore? It’s proven utility in the much more popular (ultra-) hypofractionated regimens will largely be left up to ongoing clinical protocols.

TBL: Those with a vested interest in SpaceOAR can point to numerical, if not slam-dunk, improvements in late toxicity and quality of life with the use of a rectal spacer as an adjuvant to conventional prostate radiation, but whether that’s worth its placement in all patients is a much more nuanced value judgement. | Miller, JAMA Netw Open 2020