An interventional study of Absorbable Hydrogel Spacer in Cervical Cancer, sponsored by Tianjin Medical University Cancer Institute and Hospital. Recruiting at 1 site in China. Open to female participants aged 17 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-10-29.
Sponsored by Tianjin Medical University Cancer Institute and Hospital · Not applicable, Interventional, and Treatment
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.
This is a prospective, single-center, single-arm exploratory study enrolling approximately 30 participants with cervical cancer who are scheduled to receive definitive radiotherapy. An absorbable hydrogel spacer will be implanted between the posterior cervix/vaginal wall and the anterior rectal wall before the first fraction of EBRT. The spacer procedure is performed in addition to standard oncologic treatment and does not otherwise alter the planned definitive radiotherapy or systemic therapy.
Participants will undergo longitudinal imaging to characterize the spacer throughout the course of treatment. Baseline imaging will be obtained before implantation (T0). Post-implantation MRI and planning CT will be performed at T1, followed by mid-course MRI during EBRT (T2), routine MRI before brachytherapy (T3), and follow-up MRI approximately 1 month after completion of radiotherapy (T4). Spacer thickness, volume, morphology, position, and displacement will be assessed over time.
Dosimetric analyses will evaluate the rectum and other organs at risk during both EBRT and IGBT. The primary endpoint is the cumulative rectal D2cc expressed as equivalent dose in 2-Gy fractions (EQD2) across the full course of radiotherapy. Target coverage and additional dose-volume parameters for the rectum, bladder, sigmoid colon, and small bowel will also be evaluated.
For EBRT, paired pre-spacer and post-spacer planning datasets will be used to evaluate changes in organ-at-risk dose under comparable planning conditions. Exploratory comparisons may also be performed using matched historical controls treated without hydrogel spacer implantation. Technical feasibility, procedure-related adverse events, spacer stability, and longitudinal imaging characteristics will be assessed as secondary or exploratory outcomes.
1,933 studies on the registry are indexed under Uterine Cervical Neoplasms; 578 are open to participants now.
This study's planned enrollment of 30 is below the median of 100 across 1,416 interventional studies indexed under Uterine Cervical Neoplasms.
Browse Uterine Cervical Neoplasms studies →Tianjin Medical University Cancer Institute and Hospital is the lead sponsor of 493 studies on the registry; 292 are open to participants now.
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Exclusion Criteria:
Participants will undergo implantation of an absorbable hydrogel spacer between the posterior cervix/vaginal wall and the anterior rectal wall before the first fraction of external beam radiotherapy (EBRT). Participants will subsequently receive standard definitive radiotherapy, including EBRT and image-guided brachytherapy (IGBT), according to the institutional treatment protocol. Serial MRI and CT will be performed to evaluate spacer stability and dosimetric effects throughout the course of radiotherapy.
Device: Absorbable Hydrogel Spacer
An absorbable hydrogel spacer will be implanted between the posterior cervix/vaginal wall and the anterior rectal wall before the first fraction of external beam radiotherapy (EBRT). The spacer is intended to increase the physical separation between the target region and the rectum during definitive radiotherapy. Participants will subsequently receive standard definitive radiotherapy, including EBRT and image-guided brachytherapy (IGBT). The position, morphology, and stability of the spacer and its dosimetric effects will be evaluated throughout the course of treatment.
Cumulative Rectal D2cc During the Full Course of Radiotherapy
Cumulative dose to the most exposed 2 cm³ of the rectum (D2cc) from external beam radiotherapy (EBRT) and all image-guided brachytherapy (IGBT) fractions, expressed as equivalent dose in 2-Gy fractions (EQD2) using an α/β ratio of 3 Gy. The cumulative rectal D2cc will be analyzed as a continuous variable.
Time frame: From the start of EBRT through completion of the final IGBT fraction, approximately 7-8 weeks
Proportion of Participants With Cumulative Rectal D2cc EQD2 ≤65 Gy
Proportion of participants with cumulative rectal D2cc ≤65 Gy EQD2, calculated from EBRT and all IGBT fractions using an α/β ratio of 3 Gy.
Time frame: Through completion of the final IGBT fraction, approximately 7-8 weeks
Change in Rectal D2cc Between Pre-Spacer and Post-Spacer EBRT Plans
Within-participant change in rectal D2cc between the research pre-spacer virtual EBRT plan generated using T0-CT and the clinical post-spacer EBRT plan generated using T1-CT under standardized planning conditions. The change in rectal D2cc will be reported in Gy.
Time frame: From T0-CT before hydrogel implantation to T1-CT before the first EBRT fraction, approximately 1-7 days
Proportion of Participants Completing the Planned Hydrogel-Assisted Radiotherapy Workflow
Proportion of participants who successfully undergo hydrogel implantation and complete the planned EBRT and IGBT workflow without clinically meaningful treatment interruption attributable to the study procedure.
Time frame: From hydrogel implantation through completion of the final IGBT fraction, approximately 7-8 weeks
Proportion of Participants With Procedure- or Device-Related Adverse Events
Proportion of participants experiencing adverse events or serious adverse events considered related to hydrogel implantation, the device, or the implantation procedure. Adverse events will be graded according to CTCAE version 5.0.
Time frame: From hydrogel implantation through 12 months after completion of radiotherapy
Plan to share: No — Individual participant data sharing is not planned for this study.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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