Liver Metastases Treated With Magnetic Resonance Imaging Guided Stereotactic Body Radiation Therapy: Outcomes of Tolerability, Acute Toxicity, and Quality of Life From the MOMENTUM Study

Purpose: Stereotactic body radiation therapy (SBRT) is a local treatment option for liver metastases. The introduction of magnetic resonance imaging (MRI) guided SBRT has paved the way for optimal treatment outcomes by improving tumor visualization, daily plan adaptation and margin reduction. The purpose of this study was to review the tolerability of MRI-guided liver SBRT and to present early toxicity and quality of life (QoL) outcomes from a prospective multicenter registry. Methods and Materials: All patients enrolled in the MOMENTUM study (NCT04075305) who were treated for liver metastases between April 2019 and April 2023 on a 1.5T MR-Linac were included. Descriptive statistics were used to present tolerability of treatment, acute toxicity (National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0) and Quality of Life questionnaires (QLQ-C30 and EQ-5D-5L) at baseline and 3 months after treatment. Results: A total of 135 patients (median age, 67 years; range, 31-93) were treated in 7 institutes across 4 countries. The most common primary tumor origins were colorectal (50%) and lung cancer (12%). Prescribed total SBRT doses ranged from 20.0 to 67.5 Gy, delivered in 2 to 12 fractions of 7 to 22.5 Gy per fraction (median biologically effective dose, 180 Gy; range, 59.5-540 Gy). A total of 97% of patients (n = 131) completed their treatment, with no interruptions due to poor tolerability. Up to 3 months, 14 grade 3 toxicities were reported in 12 patients (10.6%), with only 1 (0.9%) recorded as radiation therapy related (gastritis). No grade ≥4 toxicities were reported. Sixty-two and 63 patients completed the QLQ-C30 and EQ-5D-5L questionnaires at both time points, respectively. These showed a worsening of 5 to 10 points at 3 months for role functioning, nausea, fatigue, constipation, and pain. Conclusions: In this prospective cohort, 97% of treatments were well tolerated and completed successfully, with only 1 case of acute grade 3 radiation therapy related toxicity and no grade ≥4 toxicity reported. QoL outcomes showed clinically relevant worsening (defined as ≥5 points) in 5 domains, which is comparable to that of computed tomography (CT-) guided SBRT. Overall, the outcomes showed that MRI-guided SBRT is a well-tolerated and safe treatment for patients with liver metastases.