SpaceOAR hydrogel spacer in interstitial brachytherapy for intrapelvic recurrent endometrial cancer

Objective: We report the use of SpaceOAR hydrogel spacer in interstitial brachytherapy (ISBT) for a patient with intrapelvic recurrent endometrial cancer (EC).Methods and materials: A 59-year-old female patient was diagnosed with intrapelvic recurrence of EC after a definitive surgery. Despite administration of adjuvant chemotherapy, the recurrent tumour in the right para-rectal fossa increased in size. Salvage radiotherapy, including external beam radiotherapy followed by ISBT boost, was planned. We planned to inject SpaceOAR between the tumour and rectum to reduce the rectal dose in ISBT; transrectal ultrasound-guided SpaceOAR injection was performed using needle applicator insertion. This was followed by computed tomography-based image-guided brachytherapy.Results: The use of SpaceOAR allowed us to achieved both a higher dose for the clinical target volume and a lower dose for the rectum. Furthermore, no ISBT-related complications or acute toxicities were observed.Conclusions: The preliminary results suggest that SpaceOAR could be effective in increasing the efficacy of ISBT for intrapelvic recurrent EC, while reducing the associated complications.