Magnetic resonance guided radiotherapy (MRgRT) and clinical outcomes: A systematic review

INTRODUCTION: Magnetic resonance-guided radiotherapy (MRgRT) offers potential advantages over conventional computed tomography-guided radiotherapy (CTgRT), however its impact on clinical outcomes remains unclear. METHODS: We systematically reviewed the clinical effectiveness and safety of MRgRT searching three databases and three trial registries through 9 December 2024. Comparative studies were assessed for risk of bias and the certainty of evidence was evaluated. An evidence and gap map was used to visualise available data by cancer type, sample size, and outcome. RESULTS: We identified 136 primary studies, 58 ongoing trials and one systematic review. Six comparative studies (one randomised control trial (RCT) and five cohort studies across prostate, pancreatic, liver, and lung cancers) were identified. Where investigated, MRgRT did not demonstrate a statistically significant improvement in survival or local control compared with CTgRT. Two prostate cancer studies reported reduced deterioration in urinary, bowel, and sexual quality-of-life domains up to 24 months post-MRgRT. One RCT showed significant reductions in acute Grade ≥2 genitourinary (GU) (24.4% vs. 43.4%, p = 0.01) and gastrointestinal (GI) toxicity (0.0% vs. 10.5%, p = 0.003), as well as late Grade ≥2 GU (27.0% vs. 51.0%, p = 0.004) and GI toxicity (1.4% vs. 9.5%, p = 0.025). Similar reductions in toxicity were observed in two cohort studies. No safety concerns were reported in any study. CONCLUSIONS: Comparative findings were limited by short follow-up, small sample sizes, and high risk of bias. Ongoing trials may in future add to the evidence base. IMPLICATIONS FOR PRACTICE: While data from prostate cancer studies suggest potential quality of life and toxicity improvements, comparative evidence across different cancers remains sparse and of very low certainty.