Major Complications and Adverse Events Related to the Injection of the SpaceOAR Hydrogel System Before Radiotherapy for Prostate Cancer: Review of the Manufacturer and User Facility Device Experience Database

Purpose: SpaceOAR is a Food and Drug Administration-approved hydrogel injection used to create space between the prostate and rectum during prostate radiotherapy. It has shown to significantly reduce the rectal radiation dose with lower rates of rectal toxicity. Despite a high safety performance in initial trials, SpaceOAR remains in early clinical use. Thus, we examined emerging safety reports as the system becomes more widely utilized. Methods: We reviewed the SpaceOAR manufacturer website for the safety profile and complications associated with the SpaceOAR hydrogel. We then compared this with reports submitted to the Manufacturer and User Facility Device Experience (MAUDE) database. Results: The manufacturer website reported risks including pain, needle penetration, and/or gel injection into a nearby organ or blood vessel, local inflammation, infection, urinary retention, and local rectal injury or symptoms. There were 22 unique reports discussing 25 patient cases in the MAUDE database from January 2015 to March 2019, with an increasing number of reports each year up through 2018. Unique major complications including acute pulmonary embolism, severe anaphylaxis, prostatic abscess and sepsis, purulent perineal drainage, rectal wall erosion, and rectourethral fistula were reported. Conclusion: Despite well-documented clinical benefits of the SpaceOAR System, there are a number of severe and debilitating complications recently reported in proximity to gel injection. This highlights the need for further study of device complications in light of its increasing clinical use.