Hyaluronic Acid Spacer for Hypofractionated Prostate Radiation Therapy: A Randomized Clinical Trial.

Importance: Hypofractionated radiation therapy (RT) for prostate cancer has been associated with greater acute grade 2 gastrointestinal (GI) toxic effects compared with conventionally fractionated RT.

Objective: To evaluate whether a hyaluronic acid rectal spacer could (1) improve rectal dosimetry and (2) affect acute grade 2 or higher GI toxic effects for hypofractionated RT.

Design, Setting, And Participants: This randomized clinical trial was conducted from March 2020 to June 2021 among 12 centers within the US, Australia, and Spain, with a 6-month follow-up.