Broader Adoption and Future Research in Rectal Spacing

Asked whether these findings support broader adoption of rectal spacers as a standard adjunct, Martin T. King, MD, PhD, frames the study as supportive of further research into additional radiation therapy settings. He points to growing interest in rectal spacing for micro-boost radiation therapy, in which the whole prostate receives a definitive dose while an additional dose is directed at the visible tumor; since some data suggest higher tumor doses can improve outcomes, he suggests rectal spacing could help enable safer dose escalation for tumors located near the rectum. He also notes strong interest in using rectal spacers with stereotactic body radiation therapy (SBRT), and says this trial supports expanding research into these and other areas of radiation oncology.

On the significance of 3-year follow-up, King says it provides additional reassurance about both the safety and efficacy of rectal spacing. He notes that he generally favors longer follow-up, and says the combination of reduced GI toxicity and the absence of new safety signals from the original procedure leaves him confident that rectal spacers are safe through at least 3 years, and likely longer, since the spacer itself dissolves over that time frame.

Looking ahead, he outlines several open questions: further study of new indications such as micro-boost radiation therapy and SBRT, better defining optimal spacer placement techniques, and evaluating how rectal spacers appear on radiation planning scans as their use grows worldwide. He also flags the need to better define when reversing the hyaluronic acid spacer with hyaluronidase is appropriate, and highlights emerging data on how rectal spacing may affect sexual and urinary quality of life as an area he finds particularly worth pursuing.