MR-guided, daily adjusted radiation therapy on a CT-guided radiation device for the precise treatment of ultra-central lung tumors

Résumé de l'étude

You are suffering from a tumor or metastasis that is very close to the central structures within the lung (airway and/or esophagus, main bronchi), also referred to as an 'ultra-central lung tumor.' As a result, it has been recommended to perform a highly precise, so-called 'stereotactic' radiation therapy. In this study, we investigate whether daily adjusted radiation therapy using a special MR simulator and CT-guided radiation is feasible for treating such ultra-central lung tumors and whether it offers advantages over standard, non-daily adjusted radiation therapy. The common type of radiation therapy is CT-based radiation therapy: before the first radiation session, magnetic resonance (MR) or computed tomography (CT) imaging is performed. Based on this imaging, the radiation therapy is planned. All radiation sessions are then conducted according to this plan. A computed tomography scanner is integrated into the radiation device, allowing three-dimensional images to be recorded for patient positioning. In the context of daily adjusted radiation therapy, an imaging (MR imaging) is performed using an MR simulator before each radiation session. The radiation plan is then adjusted according to the imaging. Individual anatomy is subject to daily (usually small) changes, such as a decrease in tumor volume during radiation therapy, the position of the esophagus/airway relative to each other, etc. With daily adjusted radiation therapy, the radiation plan can be immediately adapted to these changes just before each radiation session. This is expected to lead to more precise targeting of the tumor while better sparing surrounding organs compared to solely CT-based radiation therapy.

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Intervention étudiée

Preparation: Before starting radiation, we perform MR imaging in the same position intended for radiation using two special MR simulators with different field strengths (MR simulation). Based on this imaging, we create your baseline radiation plan. It takes about a week to create the baseline radiation plan.

Radiation therapy: On each radiation day, MR simulation is performed again. A new radiation plan is then created based on the latest MR imaging. If this radiation plan meets the quality requirements, you will be treated on the same day with a CT-guided radiation device according to the new radiation plan. If the day's radiation plan does not meet the quality criteria, treatment can still proceed: you will receive therapy according to the original plan created during the first MR simulation, so the radiation series does not have to be interrupted. Once a week, the treatment takes a bit longer because we perform a second MR scan that provides additional information about changes in the tumor and surrounding healthy tissue under radiation.

Follow-up: The follow-up care for study participants after completing radiation therapy corresponds to the current clinical standard and is not altered by the study.

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Maladie en cours d'investigation

Ultra-central lung cancer

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Sponsor

Universitätsspital Zürich Klinik für Radio-Onkologie

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Nom du comité d'éthique approbateur (pour les études multicentriques, uniquement le comité principal)

Commission cantonale de Zurich

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Date d'approbation du comité d'éthique

11.07.2025

(BASEC)

Résultats de l'essai