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. 2024 May 1;7(5):e2410819.
doi: 10.1001/jamanetworkopen.2024.10819.

Safety and Tolerability of Online Adaptive High-Field Magnetic Resonance-Guided Radiotherapy

Jasmijn M Westerhoff  1 , Lois A Daamen  1 , John P Christodouleas  2   3 , Erwin L A Blezer  1 , Ananya Choudhury  4 , Rosalyne L Westley  5 , Beth A Erickson  6 , Clifton D Fuller  7 , Shaista Hafeez  5   8 , Uulke A van der Heide  9 , Martijn P W Intven  10 , Anna M Kirby  5   8 , Susan Lalondrelle  5   8 , Bruce D Minsky  7 , Stella Mook  10 , Marlies E Nowee  9 , Corrie A M Marijnen  9 , Kristina M Orrling  11 , Arjun Sahgal  12 , Christopher J Schultz  6 , Corinne Faivre-Finn  4   13 , Robbert J H A Tersteeg  10 , Alison C Tree  5   8 , Chia-Lin Tseng  12 , Tine Schytte  14   15 , Dustin M Silk  7 , Dave Eggert  2 , Marco Luzzara  2 , Jochem R N van der Voort van Zyp  10 , Helena M Verkooijen  1 , William A Hall  6
Affiliations

Safety and Tolerability of Online Adaptive High-Field Magnetic Resonance-Guided Radiotherapy

Jasmijn M Westerhoff et al. JAMA Netw Open. .

Abstract

Importance: In 2018, the first online adaptive magnetic resonance (MR)-guided radiotherapy (MRgRT) system using a 1.5-T MR-equipped linear accelerator (1.5-T MR-Linac) was clinically introduced. This system enables online adaptive radiotherapy, in which the radiation plan is adapted to size and shape changes of targets at each treatment session based on daily MR-visualized anatomy.

Objective: To evaluate safety, tolerability, and technical feasibility of treatment with a 1.5-T MR-Linac, specifically focusing on the subset of patients treated with an online adaptive strategy (ie, the adapt-to-shape [ATS] approach).

Design, setting, and participants: This cohort study included adults with solid tumors treated with a 1.5-T MR-Linac enrolled in Multi Outcome Evaluation for Radiation Therapy Using the MR-Linac (MOMENTUM), a large prospective international study of MRgRT between February 2019 and October 2021. Included were adults with solid tumors treated with a 1.5-T MR-Linac. Data were collected in Canada, Denmark, The Netherlands, United Kingdom, and the US. Data were analyzed in August 2023.

Exposure: All patients underwent MRgRT using a 1.5-T MR-Linac. Radiation prescriptions were consistent with institutional standards of care.

Main outcomes and measures: Patterns of care, tolerability, and technical feasibility (ie, treatment completed as planned). Acute high-grade radiotherapy-related toxic effects (ie, grade 3 or higher toxic effects according to Common Terminology Criteria for Adverse Events version 5.0) occurring within the first 3 months after treatment delivery.

Results: In total, 1793 treatment courses (1772 patients) were included (median patient age, 69 years [range, 22-91 years]; 1384 male [77.2%]). Among 41 different treatment sites, common sites were prostate (745 [41.6%]), metastatic lymph nodes (233 [13.0%]), and brain (189 [10.5%]). ATS was used in 1050 courses (58.6%). MRgRT was completed as planned in 1720 treatment courses (95.9%). Patient withdrawal caused 5 patients (0.3%) to discontinue treatment. The incidence of radiotherapy-related grade 3 toxic effects was 1.4% (95% CI, 0.9%-2.0%) in the entire cohort and 0.4% (95% CI, 0.1%-1.0%) in the subset of patients treated with ATS. There were no radiotherapy-related grade 4 or 5 toxic effects.

Conclusions and relevance: In this cohort study of patients treated on a 1.5-T MR-Linac, radiotherapy was safe and well tolerated. Online adaptation of the radiation plan at each treatment session to account for anatomic variations was associated with a low risk of acute grade 3 toxic effects.

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Christodouleas reported employment with Elekta AB during the conduct of the study. Dr Choudhury reported grants from Elekta AB, Cancer Research UK, Prostate Cancer UK, Manchester Academic Health Sciences Centre UK, and National Institute of Health Research UK (NIHR) during the conduct of the study; she reported grants from UK Research and Innovation, donations to her research fund from Bayer, BMJ Oncology and Merck, honoraria from American Society for Radiation Oncology, American Society of Clinical Oncology, Roche, AstraZeneca, and Bristol Myers Squibb, and educational support from Janssen outside the submitted work. Dr Erickson reported receiving travel funding as a board member of the American Society for Radiation Oncology. Dr Fuller reported grants, personal fees, and travel fees from Elekta AB; he reported travel support from Philips Medical and grants from National Institutes of Health (No. P30CA016672) during the conduct of the study; outside the submitted work, Dr Fuller received travel support from Varian/Siemens Healthineers and Philips Medical, Oncospace Inc, Human BioMolecular Atlas Program, Princess Margaret Hospital, and National Science Foundation, and grants and institutional support from National Institutes of Health and MD Anderson Cancer Center; in addition, Dr Fuller held a US patent (No. US 11,730,561B2) licensed to Kallisio Inc. Dr Hafeez reported support from members of the Elekta MR-Linac Consortium, including Elekta AB, Philips, The Royal Marsden Hospital, and The Institute of Cancer Research; she reported service as bladder tumor site group lead within the MR-Linac Consortium during the conduct of the study and speaker fees received from Elekta AB. Dr Van der Heide reported grants from Elekta AB and the Dutch Cancer Society (No. 14338) during the conduct of the study. Dr Intven reported receiving personal fees from Elekta AB for giving lectures outside the submitted work. Dr Kirby reported service as site lead for the Elekta MR-Linac Consortium breast tumor site working group until 2022; she reported service as president of the European Society of Radiation Oncology during the conduct of the study. Dr Lalondrelle reported grants from Elekta during the conduct of the study. Dr Nowee reported grants from Dutch Cancer Society (KWF Kankerbestrijding; grant No. 13217) and personal fees from Elekta AB including travel reimbursement and honoraria outside the submitted work. Dr Marijnen reported receiving research support from Elekta during the conduct of the study. Dr Orrling reported receiving travel support from Elekta AB. Dr Sahgal reported service as a clinical steering committee member for the Elekta MR-Linac Research Consortium and chairs the Elekta Oligometastases Group and the Elekta Gamma Knife Icon Group; he reported consulting work with Varian, Elekta AB, BrainLAB, Merck, Abbvie, and Roche; he reported service as vice president of the International Stereotactic Radiosurgery Society and cochair of the AO Spine Knowledge Forum Tumor; he reported receiving honoraria for past educational seminars for AstraZeneca, Elekta AB, Varian, BrainLAB, Accuray, Seagen Inc; he reported research grants with Elekta AB, Varian, Seagen Inc, and BrainLAB; and he reported travel compensation with Elekta AB, Varian, and BrainLAB. Dr Schultz reported travel support from Elekta AB during the conduct of the study; he reported grants from Elekta AB, Manteia Imaging, Siemens Healthineers, and Accuray outside the submitted work; and service as member of the clinical steering committee for the MR-Linac Consortium. Dr Faivre-Finn reported grants from Elekta AB, NIHR Manchester Biomedical Research Centre, and Manchester Academic Health Sciences Centre UK during the conduct of the study, and grants from Astra Zeneca outside the submitted work. Dr Tree reported receiving grants and personal fees from Elekta AB, Accuray, and Janssen; she reported travel fees, honoraria, and other institutional support for her role as chair of the MR-Linac consortium steering committee during the conduct of the study; and she reported grants from Accuray and Varian outside the submitted work. Dr Tseng reported advisory work with Sanofi; he reported receiving travel support from Elekta AB; and he reported service as Brain Tumor Site Group Lead within the MR-Linac Consortium during the conduct of the study. Dr Schytte reported serving as a member of the MR-Linac Consortium steering committee; she reported receiving honoraria and travel support by Elekta AB. Mr Eggert reported employment with Elekta AB during the conduct of the study. Dr Luzzara reported employment with Elekta AB during the conduct of the study. Dr Verkooijen reported grants from Elekta during the conduct of the study. Dr Hall reported receiving grants and travel support from Elekta AB during the conduct of the study; he reported receiving grants from the National Center for Advancing Translational Sciences (No. KL2TR001438); he reported holding equity with Sonoptima and receiving personal fees from Aktis Oncology outside the submitted work. No other disclosures were reported.

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