ESTRO 2022

Session Item

Sunday

May 08

10:30 - 11:30

Room D4

MR-guided radiotherapy

Chair: , United Kingdom;

Co-Chair: , The Netherlands

Session Code: 2200

Session Type: Proffered Papers

Track: Interdisciplinary

10:30 - 10:40

Patterns of Care and Safety in 1800 patients treated on a high-field MR-Linac platform registry

Jasmijn Westerhoff, The Netherlands

Presentation Number: OC-0419

Abstract

Abstract Title:

Patterns of Care and Safety in 1800 patients treated on a high-field MR-Linac platform registry

Authors:

Jasmijn Westerhoff¹, Lois Daamen¹, John Christodouleas², Erwin Blezer¹, Ananya Choudhury³, Rosalyne Westley⁴, Beth Erickson⁵, Clifton Fuller⁶, Shaista Hafeez⁷, Uulke van der Heide⁸, Martijn Intven⁹, Anna Kirby¹⁰, Susan Lalondrelle¹⁰, Bruce Minsky⁶, Stella Mook¹¹, Marlies Nowee⁸, Corrie Marijnen⁸, Kristina Orrling¹², Arjun Sahgal¹³, Christopher Schultz⁵, Robbert Tersteeg⁹, Alison Tree¹⁴, Chia-Lin Tseng¹³, Jochem van der Voort van Zyp⁹, Helena Verkooijen¹⁵, William Hall⁵

¹University Medical Center Utrecht, Division of Imaging and Oncology, Utrecht, The Netherlands; ²Elekta AB, Elekta, Stockholm, Sweden; ³The University of Manchester and The Christie National Health Service Foundation Trust, Radiation Oncology, Manchester, United Kingdom; ⁴The Royal Marsden NHS Foundation Trust, Radiation Oncology, London, United Kingdom; ⁵Medical College of Wisconsin, Department of Radiation Oncology, Milwaukee, Wisconsin, United States Minor Outlying Island; ⁶University of Texas MD Anderson Cancer Center Houston, Department of Radiation Oncology, Houston, Texas, United States Minor Outlying Island; ⁷The Royal Marsden NHS Foundation Trust, The Institute of Cancer Research, London, United Kingdom; ⁸Netherlands Cancer Institute, Department of Radiation Oncology, Amsterdam, The Netherlands; ⁹University Medical Center Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands; ¹⁰The Royal Marsden NHS Foundation Trust and The Institute of Cancer, Radiation Oncology, London, United Kingdom; ¹¹University Medical Center, Department of Radiation Oncology, Utrecht, The Netherlands; ¹²Lygature, ., Amsterdam, The Netherlands; ¹³Sunnybrook Health Sciences Centre-Odette Cancer Centre, Department of Radiation Oncology, Toronto, Canada; ¹⁴The Royal Marsden NHS Foundation Trust and The Institute of Cancer, Department of Radiation Oncology, London, United Kingdom; ¹⁵University Medical Center Utrecht, Department of Imaging and Oncology, Utrecht, The Netherlands

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Purpose or Objective

In 2018, the first high-field MR-Linac was introduced into clinical practice for the applicability of magnetic resonance guided radiotherapy (MRgRT). This system integrates a diagnostic 1.5 Tesla (T) MR scanner with a linear accelerator and provides online adaptation of treatment plans according to daily position of tumors and organs at risk (OAR) visualised on MR imaging. MRgRT has the potential to increase irradiation doses to the target area, whilst reducing the risk of toxicity by sparing the OARs. Here, we present patterns of care and safety after enrolment of the first 1800 patients in the Multi-OutcoMe EvaluatioN of radiation Therapy Using the MR-Linac Study (MOMENTUM) (NCT04075305).

Material and Methods

This international, multi-institutional, prospective, observational cohort study included patients ≥ 18 years receiving treatment on MR-Linac between February 2019 and October 2021 in eight institutions from five countries. Descriptive statistics were used to describe the patterns of care and safety. Acute severe toxicity was scored according to CTCAE (Common Terminology Criteria for Adverse Events) grade ≥ 3, during first three months after treatment. They were classified as possibly or likely radiation treatment related if the toxicity was not reported pre-treatment, and if nature of adverse event was likely to be related to anatomic area of treatment.

Results

At present, 1801 patients with complete baseline data were available for analysis. Of these, 1412 patients were male (78%) and the median age was 69 years (range 23-95 years). Tumor sites that were most frequently treated were prostate (n = 789; 44%), lymph nodes (n = 203, 11%) and brain (n = 200, 11%). The majority of patients received treatment for a primary tumor (n = 1284, 71%). Median of fractions per treatment was 5 (range 1-35). Currently, 1011 patients were evaluated for acute toxicity. Grade 3 or more toxicity occurred in 109 patients (11 %), of which 23 (2 %) toxicities were possibly or likely radiation treatment-related. No grade 4 or 5 acute events related to radiation were observed.

Image 1: Frequency of inclusions per tumor site

Table 1: Toxicity (≥ grade 3 of CTCAE) possibly or likely to be attributed to radiotherapy treatment

Conclusion

This study shows acute toxicity outcomes from the fast growing number of patients treated on the MR-Linac for various tumor sites. Given that less than 5 % of grade 3 toxicities, possibly or likely related to treatment, were reported without any grade 4 or 5 events, implementation of high-field online MRgRT is likely to be safe. Updated results will be reported at ESTRO.