Sagittal view of the transrectal ultrasound of the procedure of the SpaceOAR hydrogel spacer injection and interstitial needle insertion. (a) The recurrent tumour with a parenchymal and cystic component (red dotted line; tumour, yellow-dotted line; rectum); (b) Needle puncture of the cystic component of the tumour; (c) SpaceOAR was injected between the tumour and rectum (blue-dotted line; SpaceOAR); (d) After injection of the SpaceOAR; (e) Placement of the interstitial needles for the tumour.