Magnetic Resonance-Guided Adaptive Radiotherapy for Prostate Cancer: The First Results from the MOMENTUM study, an International Registry for the Evidence-Based Introduction of Magnetic Resonance-Guided Adaptive Radiotherapy.

Magnetic resonance (MR)-guided radiotherapy (MRgRT) is a new technique for treatment of localized prostate cancer (PCa). We report the 12-month outcomes for the first PCa patients treated within an international consortium ([XXXX] study) on a 1. 5T MR-Linac system with ultra-hypofractionated radiotherapy.

Patients treated with 5 × 7.25 Gy were identified. Prostate specific antigen (PSA)-level, physician-reported toxicity (Common Terminology Criteria for Adverse Events [CTCAE]), and patient-reported outcomes (PRO) (QLQ-PR25 and QLQ-C30 questionnaires) were recorded at baseline and at 3, 6, and 12 months of follow-up (FU). Pairwise comparative statistics were conducted to compare outcomes between baseline and FU.

Four-hundred-and-twenty-five patients with localized PCa (11.4% low, 82.0% intermediate, and 6.6% high risk) were included, and 365, 313, and 186 patients reached 3, 6, and 12 months FU, respectively. Median PSA level declined significantly to 1.2 ng/mL and 0.1 ng/mL at 12 months FU for the non-ADT and ADT group, respectively. The peak of genitourinary and gastrointestinal CTCAE toxicity was reported at 3 months FU, with 18.7% and 1.7% grade ≥ 2, respectively. The QLQ-PR25 questionnaire outcomes showed significant deterioration in urinary domain score at all FU moments, from 8.3 (IQR: 4.1-16.6) at baseline to 12.4 (IQR: 8.3-24.8; p=0.005) at 3 months, 12.4 (IQR: 8.3-20.8; p=0.018;) at 6 months, and 12.4 (IQR: 8.3-20.8; p=0.001) at 12 months. For the non-ADT group, physician- and patient-reported erectile function worsened significantly between baseline and 12 months FU.

Ultra-hypofractionated MRgRT for localized PCa using a 1.5T MR-Linac is effective and safe. The peak of CTCAE genitourinary and gastrointestinal toxicity was reported at 3 months FU. Furthermore, for patients without ADT, a significant increase in CTCAE erectile dysfunction was reported at 12 months FU. These data are useful for educating patients on expected outcomes and informing study design of future comparative-effectiveness studies.

Practical radiation oncology. 2022 Nov 29 [Epub ahead of print]

Frederik R Teunissen, Thomas Willigenburg, Alison C Tree, William A Hall, Seungtaek L Choi, Ananya Choudhury, John P Christodouleas, Johannes C J de Boer, Eline N de Groot-van Breugel, Linda G W Kerkmeijer, Floris J Pos, Tine Schytte, Danny Vesprini, Helena M Verkooijen, Jochem R N van der Voort van Zyp

Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands., Department of Urological Oncology, The Royal Marsden NHS Foundation Trust and the Institute of Cancer Research, London, United Kingdom., Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States., Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States., Division of Cancer Sciences, University of Manchester and Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, United Kingdom., Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States.; Elekta AB, Stockholm, Sweden., Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands., Department of Radiation Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands., Department of Oncology, Odense University Hospital, Odense, Denmark., Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada., Imaging and Oncology Division, University Medical Center Utrecht, Utrecht, The Netherlands.; Utrecht University, Utrecht, The Netherlands., Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.. Electronic address: .