High versus low dose Stereotactic Body Radiation Therapy for hepatic metastases

Introduction: Stereotactic Body Radiation Therapy (SBRT) is a treatment option for patients with liver metastases. This study evaluated the impact of high versus low dose image-guided SBRT of hepatic metastases. Methods and materials: This is a single-center retrospective study of patients with liver metastases treated with SBRT. For analyses, patients were divided into two groups: ≤100 Gy and >100 Gy near-minimum Biological Effective Doses (BED_98%). The main outcomes were local control (LC), toxicity and overall survival (OS). Cox regression analyses were performed to determine prognostic variables on LC and OS. Results: Ninety patients with 97 liver metastases (77% colorectal) were included. Median follow-up was 28.6 months. The two-year LC rates in the ≤100 Gy and >100 Gy BED_98% group were 60% (CI: 41–80%) and 90% (CI: 80–100%), respectively (p = 0.004). Grade 3 toxicity occurred in 7% vs 2% in the ≤100 Gy and >100 Gy group (p = 0.23). Two-year OS rates in the ≤100 Gy and >100 Gy group were 48% (CI: 32–65%) and 85% (CI: 73–97%), respectively (p = 0.007). In multivariable Cox regression analyses, group dose and tumor volume were significantly correlated with LC (HR: 3.61; p = 0.017 and HR: 1.01; p = 0.005) and OS (HR: 2.38; p = 0.005 and HR: 1.01; p = <0.0001). Conclusion: High dose SBRT provides significantly better local control and overall survival than low dose SBRT without increasing toxicity. When surgical resection is not feasible, high dose SBRT provides an effective and safe treatment for liver metastases.