Magnetic Resonance Imaging-guided Online Adaptive Radiotherapy of Pelvic Lymph Node Metastases

Not Applicable

Recruiting

• Conditions: Pelvic and Para-aortic Lymph Node Metastases

• Registration Number: NCT07083648
• Lead Sponsor: University of Zurich

Brief Summary

In this study, the investigators want to investigate whether online-adapted radiotherapy using a special magnetic resonance imaging (MRI) simulator and computed tomography (CT)-guided radiation therapy, is feasible and offers advantages for the treatment of pelvic lymph node metastases.

Detailed Description

MR-guided online adaptive radiotherapy has been implemented recently using MR-linac technology, where MR-imaging is combined with linac technology in hybrid systems. These systems offer MR imaging for online adaptive radiotherapy (RT) within the treatment room and with the patient in treatment position. Despite results regarding technical and clinical feasibility being promising, the high costs of MR-linacs systems and the high demands for staffing resources of MR-linacs are limiting a boarder implementation of this technology. At the Department of Radiation Oncology, University Hospital Zurich, MRI-simulations for RT planning using a dedicated scanner have been performed since 2023. The investigators have developed and implemented an MRI-only RT planning workflow followed by RT delivered at a CBCT-guided, conventional linac. The aim to expand the MRI-only workflow to online adaptive RT. This study will investigate the feasibility of MRI-guided, online adaptive SBRT for pelvic and para-aortic lymph node metastases using a dedicated MR simulator and treatment delivery using conventional CBCT-linac technology.

Study Timeline

• Status Verified: 2025-07
• Study First Submitted: 2025-07-03
• Study Start: 2025-07-16
• Study First Submitted QC: 2025-07-16
• Last Update Submitted: 2025-07-16
• Study First Posted: 2025-07-24
• Last Update Posted: 2025-07-24
• Primary Completion: 2027-06
• Study Completion: 2028-07-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Intra-pelvic and para-aortic lymph node metastases from a histologically confirmed malignancy;
• Indication for SBRT based on a multidisciplinary tumor board recommendation and / or clinical practice guideline;
• Intra-pelvic and para-aortic lymph node metastases confirmed by imaging and amenable for SBRT

Exclusion Criteria

• Large body size that would not fit the MRI-simulator bore;

• Contraindications for MRI including but not limited to

  • electronic devices such as pacemakers, defibrillators, deep brain stimulators, cochlear implants that are labeled as MR unsafe. Electronic devices labeled as MR safe or MR conditional are not a contraindication;
  • metallic foreign body in the eye or aneurysm clips in the brain;
  • severe claustrophobia;
  • hip prosthesis that are labeled as MR unsafe;

• More than 5 pelvic lymph node metastasis

• Previous radiation therapy directly overlapping with SBRT in this study and leading to exceeding tolerance of OARs;

• History of Crohn's disease, ulcerative colitis

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Primary Outcome Measures

Name	Time	Method
Rate of successfully delivered fractions	during treatment, 1-2 weeks	Feasibility is measured as a successful delivery of an MRI-adapted plan using CBCT image-guidance in another room in 90% of the SBRT fractions.

Secondary Outcome Measures

Name	Time	Method
Average improvement of coverage of planning target volume	During treatment, 1-2 weeks	Dosimetric advantage is defined as \>5% improvement in coverage of the planning target volume (PTV) or \>5% better sparing of one of the organs at risk (bowel, sigma , rectum, bladder).
Adverse Events	during SBRT, 3 months and 24 months of follow-up	Common Terminology Criteria for Adverse Events (CTCAE), version 5.0

Trial Locations

Locations (1)

Zurich University Hospital, Department of Radiation Oncology; 🇨🇭 Zürich, Zurich, Switzerland