SpaceOAR Hydrogel Spacer

SpaceOAR Hydrogel is a gel-like substance that is implanted between the prostate and rectum to reduce side effects during radiation therapy treatment.

What is SpaceOAR?

Radiation therapy for prostate cancer involves the safe delivery of radiation to the prostate, while limiting the impact to surrounding healthy organs such as the rectum. SpaceOAR® is an absorbable hydrogel that is injected between the prostate and rectum to create a temporary space, reducing the amount of radiation exposure to the rectum.

Minimising side effects

Although radiation therapy is effective in treating prostate cancer, the risk of side effects remain. The major organ at risk (OAR) of radiation therapy to the prostate is the rectum, which sits directly below the prostate gland. The injection of SpaceOAR temporarily moves the rectal wall away from the prostate during radiation therapy. Studies have shown that patients injected with SpaceOAR prior to their radiation therapy treatment experience less rectal pain, urinary incontinence and late rectal toxicity, and increased sexual quality of life, compared to those treated without SpaceOAR.1,2

Is SpaceOAR safe?

SpaceOAR can be safely used in the body. It is made from two liquids that when combined form a soft gel-like synthetic material which mostly consists of water and is biodegradable. The material used in SpaceOAR is also used in other implants such as surgical sealants used on the eye, brain and spine.3 The hydrogel remains in place during the course of radiation therapy and following treatment, liquefies and is naturally absorbed by the patient’s body within six months.3 For more information, visit the SpaceOAR website.

The procedure

SpaceOAR is injected by a urologist in a short procedure, typically taking less than one hour.

Further information

For further information on whether SpaceOAR may be suitable for you, please contact the Bowen Icon Cancer Centre team on (04) 896 0200 or by emailing


For a full list of references, click here.
  1. Hamstra DA, Mariados N, Sylvester J, Shah D, Karsh L, Hudes R, Beyer D, Kurtzman S, Bogart J, Hsi RA, Kos M. Continued benefit to rectal separation for prostate radiation therapy: final results of a phase III trial. International Journal of Radiation Oncology* Biology* Physics. 2017 Apr 1;97(5):976-85.
  2. Hamstra DA, Mariados N, Sylvester J, Shah D, Gross E, Hudes R, Beyer D, Kurtzman S, Bogart J, Hsi RA, Kos M. Sexual quality of life following prostate intensity modulated radiation therapy (IMRT) with a rectal/prostate spacer: Secondary analysis of a phase 3 trial. Practical radiation oncology. 2018 Jan 1;8(1):e7-15.
  3. Augmenix, Inc. (2020). SpaceOAR Hydrogel. Retrieved on 17 February 2020 from

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