The patterns of care, tolerability and safety in the first year of a novel high field MR-linac
van Otterloo, S. R. D. Christodouleas, J. P. Blezer, E. L. A. Cobben, David Erickson, B. A. Fuller, C. D. Hafeez, S. Kirby, A. Lalondrelle, S. Mook, S.
van Otterloo, S. R. D.
Christodouleas, J. P.
Blezer, E. L. A.
Cobben, David
Erickson, B. A.
Fuller, C. D.
Hafeez, S.
Kirby, A.
Lalondrelle, S.
Mook, S.
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Abstract
Purpose/Objective(s): High field MR-Linacs are promising because
they may enable unique anatomic and response adaptive treatment
paradigms. The first commercial device received regulatory approval
in late 2018. Because high field MR-guided therapy is new, little is
known about how clinicians are using it, how patients tolerate daily
high field MRIs and the toxicity patterns of such treatments. Herein
we report the first years’ experience within an international registry
study (MOMENTUM).
Materials/Methods: The MOMENTUM Study (NCT04075305), a project
of the MR-Linac Consortium, is an international registry that collects
clinical and technical patient data with informed consent. All patients
treated on an MR-Linac at participating centers are eligible. We reviewed
the experience of patients treated from Dec. 5th 2018 to Jan. 15th 2020 and
used descriptive statistics to describe the patterns of care, tolerability
(defined as the percent of patients discontinuing the MR-Linac course
early) and safety (defined by grade 3-5 CTCAE v.5 acute toxicity within 3
months of the end of treatment).
Results: The study cohort includes 393 patients treated at seven institutions
in four countries (Netherlands, U.K., U.S. and Canada) and
represents over 50% of all patients treated globally with high field MRguided
therapy in the first year after regulatory approval. Median age was
68 years (range 29-93 years) and 78% were male. There were 23 different
tumor sites treated the most common being prostate (32%), lymph node
oligometastases (20%), rectum (11%), brain (7%), and oropharynx (6%).
Radiation of the primary tumor (71%) was the most common clinical
indication followed by regional lymph node (19%), distant metastases
(8%) and cancer recurrence at the primary tumor site (2%). In the total
cohort, 51% (150/395) had contours adjusted with every fraction (adapt-toshape).
In the subset for whom complete course of therapy data was
available (n Z 228), the median number of fractions per course was 5
(range: 1-35) and 97% (222/228) had radiotherapy on the MR-Linac only.
Two (1%) MR-Linac courses were discontinued early. One discontinuation
was due to technical problems and in one case the treating physician
decided to discontinue treatment after disease progression on imaging and
clinical decline of the patient. In the subset for whom complete acute toxicity data was available (nZ97), acute grade 3 toxicity occurred in 4%
and grade 4-5 toxicities were not observed.
Conclusion: In the first year after initial regulatory approval of high field
MR-guided therapy, we observed a wide variety of treatment sites and
indications. Daily high field MR was well tolerated and our initial acute
toxicity assessment was reassuring.
Description
Date
2020
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
van Otterloo SRD, Christodouleas JP, Blezer ELA, Cobben D, Erickson BA, Fuller CD, et al. The patterns of care, tolerability and safety in the first year of a novel high field MR-linac. International Journal of Radiation Oncology Biology Physics. 2020;108(3):S65-S