Hydrogel Spacer During Definitive Radiotherapy for Cervical Cancer

This prospective, single-center study will evaluate the feasibility, spatial stability, and dosimetric effects of an absorbable hydrogel spacer placed between the cervix/vagina and rectum before definitive radiotherapy for cervical cancer. Approximately 30 participants will receive hydrogel spacer implantation before the first fraction of external beam radiotherapy (EBRT), followed by standard definitive radiotherapy including EBRT and image-guided brachytherapy (IGBT). Serial magnetic resonance imaging (MRI) and computed tomography (CT) will be used to assess spacer position, thickness, and stability throughout treatment. Radiation doses to the rectum and other organs at risk will be evaluated across the full course of radiotherapy. The primary objective is to assess the effect of the hydrogel spacer on cumulative rectal dose while maintaining adequate target coverage. Procedure-related safety and feasibility will also be evaluated.