Liver metastases treated with MRI-guided SBRT: Outcomes of tolerability, acute toxicity and quality of life from the MOMENTUM study.

Abstract

Purpose/objective(s): 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 improved tumor visualization, daily plan adaptation and margin reduction. The purpose of this study is to review tolerability of MRI-guided liver SBRT and to present early toxicity and quality of life (QoL) outcomes from a prospective multicenter registry.

Materials/methods: All patients enrolled in MOMENTUM study (NCT04075305) who were treated for liver metastases between April 2019-April 2023 on a 1.5T MR-Linac were included. Descriptive statistics were used to present tolerability of treatment, acute toxicity (CTCAEv5.0) and QoL (QLQ-C30 and EQ-5D-5L) at baseline and three months after treatment.

Results: 135 patients (median age 67 years, range 31-93) were treated in seven institutes across four countries. The most common primary tumor origins were colorectal-(50%) and lung cancer(12%). Prescribed total SBRT doses ranged from 20.0-67.5 Gy, delivered in 2-12 fractions of 7-22.5 Gy per fraction (median BED 180Gy (range 59.5-540Gy). 97% of patients (n=131) completed their treatment and there were no interruptions due to poor tolerability. Up to three months, fourteen grade three toxicities were reported in twelve patients(10.6%), with only one(0.9%) recorded as radiotherapy related (gastritis). No grade≥4 toxicities were reported. 62 and 63 patients completed the QLQ-C30 and EQ-5D-5L questionnaires at both time points respectively. These showed a worsening of 5-10 points at three months for role functioning, nausea, fatigue, constipation and pain.

Conclusion: In this prospective cohort, 97% of treatments were well tolerated and completed successfully with only one acute grade three radiotherapy-related toxicity and no grade≥4 toxicity reported. QoL outcomes showed clinically relevant worsening (defined as ≥5points) in five domains, which is comparable to CT-guided SBRT. Overall, outcomes showed that MRI-guided SBRT is well-tolerated and a safe treatment for patients with liver metastases.