UCLA Journal of Radiation Oncology SPRING 2024 - Flipbook - Page 37
UCLA RADIATION ONCOLOGY JOURNAL
Moving forward, the use of MRgRT and real-time adaptive planning is currently being studied and
implemented in a variety of disease sites and clinical situations, including central nervous system
tumors,50, 62 head and neck cancers,50 and breast and lung neoplasms50, 62, 63 as well as re-irradiation64
and single fraction metastatic cases,65, 66 and may even be expanded to other situations where realtime, high-resolution soft tissue imaging is crucial, such as palliative celiac plexus irradiation67, 68, 69(Fig.
3). Additionally, MRgRT capabilities will continue to progress as well. Beyond motion management
and adaptive planning, MRI-specific functional imaging represents a future method through which
MRgRT can continue to demonstrate its value.62, 70, 71 For example, diffusion-weighted imaging has
been identified as a potential biomarker for treatment response and could be incorporated into the
MRgRT treatment process for dose escalation of non-responsive disease or dose de-escalation of rapidly
responding disease.4 The expansion of MRgRT to additional clinical situations and the continued
development and improvement of the adaptive treatment process will further support the economic
justification of this promising technology.
Disease
Site
Disease
Scenario
Abdomen
LAPC
1°
Liver
Oligo-
metastases
Breast
Earlystage
H&N
GU
Bladder|Prostate
Bulky
node+
Thorax
Central
tumor
Mobile,
peripheral
tumor
Need
Online
adaptiveRT
MRset-up
localization
→
Clinical
Cinegating
Offline
adaptiveRT
Figure 3. Utilization of MRI-guided radiation therapy (MRgRT) technology in a variety of disease sites and scenarios. Reproduced with
permission from: Fischer-Valuck BW, Henke L, Green O, et al. Two-and-a-half-year clinical experience with the world's first magnetic
resonance image guided radiation therapy system. Adv Radiat Oncol, 2:485–493. Copyright Elsevier (2017). No changes were made to this
figure from the original publication.
As an emerging technology, a sufficient body of evidence demonstrating the benefit of MRgRT is needed
to successfully argue for its incorporation into standard of care of radiation paradigms. A recent survey
investigation highlighted the potential challenges associated with widespread adoption of MRgRT based
on interviews of personnel involved with MRgRT, revealing that lack of current evidence of clinical
benefit was a primary concern surrounding its implementation.19 Certainly, additional evidence,
including not only traditional objective oncologic outcomes but also more thorough cost-effectiveness
analyses72, 73 and subjective measures like patient-reported outcomes,74 would help to further support
the MRgRT value proposition. However, emerging technology also frequently outpaces the evidence
supporting its use, and thus our field is in the position where we must consider and respect the need
for evidence prior to widespread implementation of MRgRT while simultaneously respecting the
drive to enable our patients to experience the intuitive but untested benefits of MRgRT. Additionally, it
should be acknowledged that technology trials are challenging to conduct,75 and it is often infeasible to
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