Magnetic Resonance-Guided Radiation Therapy for Head and Neck Cancers

Abstract

Despite the significant evolution of radiation therapy (RT) techniques in recent years, many patients with head and neck cancer still experience significant toxicities during and after treatments. The increased soft tissue contrast and functional sequences of magnetic resonance imaging (MRI) are particularly attractive in head and neck cancer and have led to the increasing development of magnetic resonance-guided RT (MRgRT). This approach refers to the inclusion of the additional information acquired from a diagnostic or planning MRI in radiation treatment planning, and now extends to online high-quality daily imaging generated by the recently developed MR-Linac. MRgRT holds numerous potentials, including enhanced baseline and planning evaluations, anatomical and functional treatment adaptation, potential for hypofractionation, and multiparametric assessment of response. This article offers a structured review of the current literature on these established and upcoming roles of MRI for patients with head and neck cancer undergoing RT.

The Evolving Role of Stereotactic Body Radiation Therapy for Head and Neck Cancer: Where Do We Stand?

“…Furthermore, recent advances in RT technology such as magnetic resonance-guided radiation therapy (MRgRT) for HNCs allows precise treatment, facilitates tighter PTV margin/smaller irradiated volumes, evaluates tumor response with functional imaging, i.e., DWI, with possibly responseadaptive RT. However, further research is required for the evaluation of predictive MR imaging biomarkers, and the use of SBRT with MRgRT for patients with HNC who cannot tolerate long course RT [81]. Moreover, the impact of SBRT for HNC in the palliative setting aiming to improve HNC outcomes in patients who are unable to tolerate curative-intent RT is going to be investigated by the CCTG HN13 phase III randomized controlled trial (SBRT vs standard palliative RT).…”

Advances in and applications of imaging and radiomics in head and neck cancer survivorship

“…MRI can improve the precision of radiotherapy delivery, with many cancer centres worldwide now having access to linear accelerators with integrated MRI units [18]. These improvements in infrastructure, coupled with a recognized need to explore adaptation and de-escalation/sparing of radiation to key organs at risk, has given way to a new wave of trials investigating MRI-based adaptive radiotherapy [19 ▪ ]. Clinical trials, such as INSIGHT-2 (NCT04242459) and DEHART (NCT04477759), are underway to determine the impact of these protocols on patient outcomes, and show encouraging preliminary findings [20].…”

Quantitative dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer: A systematic comparison of different modelling approaches

“…Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a promising quantitative imaging modality for assessing tissue response to radiation [5] , [6] . DCE-MRI involves image acquisitions before, during and after intravenous injection of a contrast agent (CA).…”

“…Tissue microvasculature and hypoxia can influence tissue response to radiation [9] , and may serve as prognostic or predictive biomarkers. Parameter maps from voxel-wise calculations may capture tumour heterogeneity better and allow definition of intra-tumoural targets for dose painting [6] . However, most studies have reported associations between mean parameter distributions and radiotherapy outcome [10] .…”

“…The large number of models also results in many candidates for prognostic or predictive biomarkers. The most promising DCE-MRI biomarker for HNC is K trans from TM, describing the transfer of contrast from the plasma space to the extracellular extravascular space (EES), but there are potentially additional useful biomarkers [6] . A more thorough comparison of DCE-MRI parameters from different models could help select which parameters merit further investigation.…”