MR-guided RAdiotherapy to Breast With Dose Escalation to regionaL Lymph NodEs

Study Overview
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Brief Summary
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Radiotherapy to the breast and lymph nodes is routinely planned using CT scans. The introduction of magnetic resonance imaging (MRI) has the potential to better visualise the lymph nodes and so define a smaller treatment area or 'target'. This means that the dose delivered to the target could be increased without increasing the dose to normal tissues. The MIRABELLE study is designed to test if this is possible by recruiting patients diagnosed with breast cancer including lymph node disease. The investigators will ask participants to have a CT scan and an MRI scan before they have radiotherapy. The investigators will then plan radiotherapy using both these scans and compare the possible dose delivered to the lymph nodes using the MRI and CT defined lymph nodes. This will not affect the patient's future treatment.

Detailed Description
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MR imaging has the potential to improve both the localisation of pan-LN treatments and the subsequent treatment delivery using MR-linac technology. The MIRABELLE study will apply the MR sequences developed in LN-negative volunteers/patients to the context of node-positive breast cancer patients with the aim of reducing the delineated nodal volume thereby facilitating dose-escalation to involved LNs. The benefit of using MRI for LN localisation as compared to conventional CT imaging will be investigated by determining whether a higher dose can be delivered using MRI- as compared to CT-based delineation. Any increase in dose will be deemed a success as this has potential to improve tumour control. In addition, inter-observer errors in outlining will be explored to investigate whether these are reduced using MRI. Reduced inter-observer errors would result in smaller margins for error such that less normal tissue could be irradiated.

Official Title
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MR-guided RAdiotherapy to Breast With Dose Escalation to regionaL Lymph NodEs

Conditions
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Breast Cancer

Intervention / Treatment
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* Procedure: Radiotherapy planning using both CT and MRI scans


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥18 years Female or male Invasive carcinoma of the breast (left or right-sided) cT1-T4,N3,M0-1 disease Due to proceed to primary treatment (chemo, surgery, radiotherapy and/or endocrine therapy) Histopathological involvement of axillary lymph nodes confirmed on FNA or Bx Likely to undergo locoregional radiotherapy as part of their breast cancer management Exclusion Criteria: Implanted pacemakers and/or pacing wires Cochlear implants Programmable hydrocephalus shunts Implanted neurostimulation systems Implanted drug infusion pumps Ferromagnetic implants Claustrophobia

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Radiotherapy planning<br>Radiotherapy planning using both CT and MRI scans | Procedure: Radiotherapy planning using both CT and MRI scans<br>* Patients' radiotherapy will be planned using CT and MRI scans in order to establish the best methodology for planning of radiotherapy for nodal disease<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The number of patients in whom a higher dose can be delivered to the level IV (SCF) nodes without breaching brachial plexus constraints on the radiotherapy plans created using MR images compared with CT images | MR images are acquired with patient in a position as close as possible to the radiotherapy CT planning position. Images are acquired in a radiotherapy CT scanner with patient in a position replicating that achieved in the MRI scanner. The images are imported into a treatment planning system and consensus lymph node volume agreed between an expert radiation oncologist and MR radiologist. All pan-LN will be delineated on co-registered MRI sequences and on CT (using ESTRO guidelines) by 7 observers. | During a radiotherapy planning process, an average of 2 weeks |