Introduction: The SpaceOAR® hydrogel system separates the prostate and rectum to reduce rectal irradiation during prostate radiotherapy. However, it could induce rectal toxicity.
Case presentation: A 75-year-old man with localized prostate cancer underwent external beam radiotherapy with the use of SpaceOAR® System. However, postimplant magnetic resonance imaging showed hydrogel infiltration to the rectum. Three months after implantation, he complained of bowel symptoms, including bloody stool. Colonofiberscopy and computed tomography revealed a rectal ulcer associated with SpaceOAR® hydrogel insertion. He was treated with fasting, fluid replacement, and blood transfusion. One year after implantation, complete healing was confirmed during outpatient follow-up.
Conclusion: To our knowledge, this is the first report of a rectal ulcer associated with SpaceOAR® hydrogel insertion assessed by magnetic resonance imaging beforehand. Postimplant magnetic resonance imaging evaluation might be a useful follow-up tool in such cases.
Keywords: adverse event; prostate cancer; radiotherapy; rectal ulcer; spacer.
© 2020 The Authors. IJU Case Reports published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Urological Association.