Evidence-Based Implementation of Magnetic Resonance Guided Radiotherapy: Patient Experiences and Early Clinical Outcomes

The MR-Linac combines magnetic resonance imaging (MRI) with radiation for the treatment of tumors. It thereby enables the acquisition of MRI immediately before, during, and after treatment. Due to the superior accuracy of MRI compared with conventional CT imaging, radiotherapy can be delivered with greater precision. This may lead to improved treatment outcomes across various tumor types, for instance through a reduction in treatment-related toxicity or improved chances of treatment success.

However, the implementation of a complex system such as the MR-Linac also presents several challenges. It requires additional specialized personnel to acquire and interpret MRI. Furthermore, individual treatment sessions are longer, though it is expected that some treatments may be delivered in fewer sessions (fractions). This increased treatment duration is partly attributable to the additional time required for MRI acquisition.

This thesis on the implementation of the MR-Linac has demonstrated that the treatment is safe. In a large patient cohort treated for a wide range of diagnoses, very few severe adverse events were observed. In addition, patients generally tolerated the longer treatment sessions well and reported positive experiences. When radiation oncologists are not continuously present during treatment but available on demand, overall treatment time does not increase, thereby supporting an efficient workflow.

Moreover, early clinical outcomes of MR-Linac treatments have been assessed in patients with prostate, rectal, and pancreatic cancer. These findings are promising and provide a foundation for further research focusing on whether this treatment is superior to the current standard of care.