Alexandra "Xan" Oakley | PCRI Educational Writer

SpaceOAR is a new rectal protection product for men with prostate cancer undergoing radiation therapy. SpaceOAR reduces the risk of rectal toxicity, also known as radiation enteropathy, a potential side effect of radiation that can be permanent after radiation.


SpaceOAR stands for Spacing Organs at Risk. This system uses a gel which is placed between the prostate and the rectum prior to radiation treatment, with a minimally invasive procedure. A small needle is inserted into the space between the rectum and the prostate and the doctor uses ultrasound imaging to gently inject the gel. The inserted gel (called hydrogel) pushes the rectum outside the area of radiation. The procedure takes about 30 minutes and is typically done in a hospital, surgery center, or doctor's office. Patients should be able to immediately resume their normal activities after the procedure, but should check with their doctor for any restrictions associated with their radiation treatment. SpaceOAR hydrogel is made from polyethylene glycol, a polyether compound that is often used in medications and even makeup products due to the fact that it is non-toxic and well tolerated by the human body.

SpaceOAR is called a hydrogel because it contains mostly water. It is not broken down by radiation, so the radiation does not change the hydrogel’s chemical properties, safety, or effectiveness. The hydrogel remains in place for 3 months, the length of radiation treatment, but is then absorbed into the body and excreted through the patient’s urine. Nothing is left behind and there are no negative side effects.

The three year study from the SpaceOAR System Prostate Cancer US Pivotal Clinical Trial showed a lower incidence of rectal toxicity compared to radiation-treated men without SpaceOAR. At the 2016 American Society for Radiation Oncology Annual Meeting in Boston, MA, Dr. Hamstra presented the 3-year results from the SpaceOAR System Prostate Cancer US Pivotal Clinical Trial. To quote: “Following radiotherapy through 3 years no SpaceOAR patients (0%) experienced grade 2 or worse late rectal toxicity, compared to 5.7% in the Control patients (p=0.012). Additionally, at 3 years the average SpaceOAR patient bowel QOL was slightly better than before radiotherapy (+0.48 points), while the control patients QOL had significantly declined (-5.3 points, p=0.05).”


In the same way you prepared for the prostate biopsy, aspirin, aspirin by-products (i.e., Excedrin, Ecotrin, St. Joseph Aspirin), blood thinners, anti-inflammatory medications (i.e., Motrin, Advil, Ibuprofen, Naproxen, Daypro, Coumadin, Plavix, Persantine) and mega dose Vitamin E must be discontinued 5 days before your procedure as directed by your primary care physician and/or cardiologist.


Assuming no specific allergies, take Ciprofloxacin 500mg 1 tablet twice a day for 3 days, starting one day before the procedure. 


Continue Ciprofloxacin as prescribed by the physician. Bring Valium and Hydrocodone/APAP to your appointment. The physician will let you know when to take these medications or might provide other analgesics. If you have not had a bowel movement by 2 hours before your appointment, then use Fleet's Enema. This can also be purchased from any pharmacy. Use 2 hours prior to your appointment to empty the lower bowels. Please follow the package instructions. Eat a light breakfast and continue to take all of your medications as usual (if applicable). A soft, bland, and low-fat diet is recommended to start the day be-fore your appointment to help reduce gas for the scan. Some examples are: No raw vegetables, spicy foods, dairy products, beans, etc.


Continue and complete your last day of Ciprofloxacin as prescribed and resume blood thinners, assuming there is no ongoing bleeding. 


SpaceOar is not for everyone getting radiation. However, in those men who are more predisposed to bowel toxicity, SpaceOar is an important new tool that can reduce the risk of rectal dam-age, though most patients do not have severe rectal damage after radiation therapy for prostate cancer.