Lawrence I. Karsh, MD, FACS, presented “SpaceOAR Hydrogel – Prostate-Rectum Spacing in Radiation Therapy at the International Prostate Cancer Update on January 27, 2018 in Beaver Creek, Colorado.

How to cite: KarshLawrence I. “SpaceOAR Hydrogel – Prostate-Rectum Spacing in Radiation Therapy” January 27, 2018. Accessed Mar 2024.

SpaceOAR Hydrogel – Prostate-Rectum Spacing in Radiation Therapy


Lawrence I. Karsh, MD, FACS, discusses the use of SpaceOAR Hydrogel to reduce risk of rectal complications and improve quality of life (QOL) outcomes when treating prostate cancer with radiation therapy. He also summarizes supporting clinical evidence, describes the physical application of the gel, and lists players currently offering coverage for the procedure.

The Need for Prostate-Rectum Spacers

While radiation therapy is one of the most common treatments for prostate cancer, it can too often lead to devastating urinary, gastrointestinal, and sexual complications. Due to the rectum’s proximity to the prostate, rectal radiation is inevitable without preventative measures. Radiation toxicity in the rectum can cause bleeding, urgency, pain, fistulas, and QOL loss. Consequently, the rectum becomes a radiation dose-limiting factor. However, creating a space between the prostate and the rectum would alleviate these issues.

SpaceOAR Hydrogel

SpaceOAR Hydrogel is a substance made of mostly water and polyethylene glycol (PEG). It can create an approximately 1.3cm barrier between the prostate and the rectum. This barrier reduces the radiation exposure to the anterior rectum during prostate cancer treatment. As a result, the risk of rectal complications decreases, and clinicians are able to offer higher radiation doses.


Clinicians apply the liquid hydrogel into the perirectal fat, between the rectal wall and the Denonvilliers’ fascia, through an 18G transperineal needle. The gel solidifies within ten seconds. Afterward, the gel spacer lasts about three months. It safely absorbs into the body after six months.

According to a United States Pivotal study, clinicians rated the application process 99% “easy” or “very easy.” Correspondingly, there was a 99% rate of technical success. In other words, SpaceOAR Hydrogel was proven to be a safe, effective, and well-tolerated procedure that places minimal stress on the clinician.