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Spacer hydrogels reduce side effects in men undergoing prostate cancer radiotherapy.

The rectal spacer hydrogels were designed to reduce radiation exposure to the organs surrounding the prostate during prostate radiotherapy. The reduction in radiation exposure to surrounding organs can reduce the side-effects such as rectal bleeding, loose bowel motions, urinary incontinence and impotence. (See references 1,2,3) .

Rectal spacer hydrogels are a soft gel implanted between the prostate and rectum to create a space. This space is important as it pushes the rectum away from the prostate and therefore, the radiotherapy field. This allows a maxim dose of radiotherapy to be delivered to the prostate gland and, therefore, to the prostate cancer whilst avoiding unnecessary irradiation of surrounding tissue. This, therefore, minimises harmful and potentially unpleasant side effects.

The gel is implanted through a minimally invasive procedure under ultrasound guidance. The spacer procedure is usually performed under local anaesthetic. The gel remains in place for up to six months whilst it is naturally absorbed by the patient’s body. 

Spacer hydrogels have been implanted in over 50,000 men worldwide and evaluated in over 60 publications. The studies have consistently found that spacer hydrogels are safe and effective.


The studies in patients undergoing prostate cancer radiotherapy report benefits, including:

  • A reduction in rectal toxicity from radiation from 9.2% in the control group vs 2% in the group receiving the SpaceOAR gel.
  • Urinary incontinence was reduced from 19.6% in the control group to 4.3% in the SpaceOAR hydrogel group.
  • A reduction in the decline of bowel Quality of Life from 20.5% in the control group vs 5.4% in the hydrogel spacer group
  • Potent men were twice as likely to retain erections sufficient for intercourse in the group who received the hydrogel rectal spacer before prostate radiotherapy. 37.5% control vs 66.7% treated.

Author Mr Neil A Haldar MD MBBS FRCS UROL

(See references 1, 2, 3)


  1. Hamstra D, Mariados N, Sylvester J et al. Continued Benefit to Rectal Separation for Prostate RT: Final Results of a Phase III Trial.
    Int J Radiat Oncol Biol Phys. 2017 Apr 1;97(5):976-985. doi: 10.1016/j.ijrobp.2016.12.024. Epub 2016 Dec 23.
  2. Hamstra D, et al. Evaluation of sexual function on a randomised trial of a prostate rectal spacer. J Clin Oncol 35, 2017
  3. Hamstra DA, Mariados N, Sylvester J et al. Sexual quality of life following prostate intensity modulated radiation therapy (IMRT) with a rectal/prostate spacer: Secondary analysis of a phase 3 trial.
    Pract Radiat Oncol. 2018 Jan – Feb;8(1):e7-e15. doi: 10.1016/j.prro.2017.07.008. Epub 2017 Jul 19.
    Jan – 2018 Jan – Feb;8(1):e7-e15. doi:
  4. SpaceOAR, What is SpaceOAR® Hydrogel?: https://www.businesswire.com/news/home/20170829005780/en [accessed February 2018]
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