Spontaneous remission of rectal ulcer associated with SpaceOAR hydrogel insertion in radiotherapy for prostate cancer.

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.