Absorbable Hydrogel Spacer Use in Prostate Radiotherapy: A Comprehensive Review of Phase 3 Clinical Trial Published Data


To provide an update on SpaceOAR® System, a FDA approved hydrogel indicated to create distance between the prostate and rectum which has been studied in phase 2 and 3 clinical trials. Here we review and summarize these clinical results including: the safety of prostate-rectum spacer application technique, the implant quality and resulting rectal dose reduction, acute and long term rectal, urinary and sexual toxicity as well as patient reported outcomes.


A prospective, randomized patient-blinded clinical study was performed comparing image-guided intensity modulated prostate radiotherapy (IG-IMRT) (79.2Gy in 44 fractions) in men with or without prostate-rectum hydrogel spacer. Patients were followed for 3 years, allowing for assessment of long-term safety and efficacy.


Spacer application was well tolerated with a 99% technical success rate. The mean additional space created between the prostate and rectum was just over 1cm which allowed for significant rectum and penile bulb radiation dose reduction, resulting in less acute pain, lower rates of late rectal toxicity, and improved bowel and urinary QOL scores from 6 months onward. Improvements in sexual QOL were also observed at 37-months in baseline-potent men, with 37.5% of Control and 66.7% of Spacer men capable of “erections sufficient for intercourse”.


Prostate-rectum hydrogel spacer application is a relatively safe technical procedure which is well tolerated and has a high technical success rate. Spacer application significantly reduces rectal radiation dose, and results in long-term reductions in rectal toxicity as well as improvements in bowel, urinary and sexual QOL

Urology. 2017 Nov 23. pii: S0090-4295(17)31213-X. doi: 10.1016/j.urology.2017.11.016

Author Information
Lawrence Karsh1, MD, Eric Gross 1, Christopher M. Pieczonka2, Philip J. Aliotta3, Christopher J. Skomra 3, Lee E. Ponsky4, Peter T. Nieh5, Misop Han6, Daniel A. Hamstra7, Neal D. Shore8

1 The Urology Center of Colorado, Denver, Colorado.
2 Associated Medical Professionals of NY PLLC, Syracuse, New York.
3 Western New York Urology Associates, Cheektowaga, New York.
4University Hospitals Case Medical Center, Cleveland, Ohio.
Emory University, Atlanta, Georgia.
The Johns Hopkins University, Baltimore, Maryland.
7The Department of Radiation Oncology, Beaumont Hospital, Dearborn, MI.
8 Carolina Urologic Research Center, Myrtle Beach, South Carolina.  

Go Beyond The Abstract: Read an Original Commentary By Neal Shore

Watch: SpaceOAR® Hydrogel Application Video performed by: Marcio Fagundes

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