Faculty, Staff and Student Publications

Publication Date

8-14-2025

Journal

Brachytherapy

DOI

10.1016/j.brachy.2025.06.010

PMID

40816920

PubMedCentral® Posted Date

8-14-2025

Abstract

Purpose: To report on primary outcomes and dosimetric results of a prospective clinical trial and protocol for use of iterative intraoperative magnetic resonance imaging (iMRI) in gynecologic brachytherapy.

Methods: Patients with locally advanced cervical or vaginal cancer (FIGO stages IB2 - IVA, and stage II-IVA, respectively) undergoing pulsed dose rate (PDR) brachytherapy were enrolled in a prospective clinical trial (NCT03634267) using iterative 3T iMRI during brachytherapy implant placement. Applicator and optional interstitial needles were placed under iMRI guidance in a 3T clinical MRI scanner. Imaging, dosimetry and clinical outcomes (local control (LC), recurrence-free survival (RFS), overall survival (OS)), and acute and long-term toxicity were evaluated prospectively and confirmed by chart review. To explore dosimetric gains, an EQD2 estimate comparing iMRI-guidance versus standard of care guidance, as well as a 3-patient analysis of dose changes with iMRI-guided optimization was included.

Results: Fourteen patients underwent iMRI-guided brachytherapy. Seventy percent (70%) of patients presented with FIGO stage III disease or higher. Median follow-up was 44 months. . Patients had 2-year median LC, RFS, and OS rates of 83.3%, 76%, and 84.6%, respectively. Acute toxicities were minimal with one (1) case of grade 3 nausea. No grade 3 or higher long-term toxicities were observed. Median operating room (OR) time was 283 minutes (range 174-380 mins). On exploratory analysis, implant placement performed with iMRI guidance demonstrated higher HR-CTV D90 doses (mean difference of +784.7 cGy, p = NS) were achieved compared to US and CT guided implantation in the same patients.

Discussion: iMRI-guidance for gynecologic brachytherapy is safe, associated with minimal high-grade toxicity and excellent clinical outcomes. Future studies to optimize resource use, image acquisition efficiency, and identifying predictive imaging features are warranted.

Keywords

Brachytherapy implant, Cervical cancer, Image guidance, Intraoperative MRI, Pulsed dose rate (PDR), Vaginal cancer

Published Open-Access

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