[A CASE OF ABSCESS FORMATION FOLLOWING HYDROGEL SPACER FOR PROSTATE CANCER RADIOTHERAPY]

The patient was a 79-year-old male who underwent external-beam radiation therapy combined with hormone therapy for prostate cancer. A hydrogel SpaceOAR was implanted to prevent adverse rectal events before stereotactic radiotherapy using Cyberknife. After completion of external irradiation, the patient developed a fever and was diagnosed with a prostatic abscess based on clinical and computed tomography findings. Magnetic resonance imaging showed the prostatic abscess consistent with SpaceOAR insertion site. Despite treatment with antibiotic agents, the patient's inflammatory response did not improve. Transurethral resection of the prostatic abscess and vesicostomy were performed for drainage, following which the postoperative inflammatory response improved rapidly. In this case, the SpaceOAR may have partially penetrated into the prostatic capsule when it was implanted, and a urinary tract infection may have occurred due to urinary retention or placement of a urethral catheter, resulting in the formation of an abscess.