Stereotactic Body Radiation Therapy (SBRT) for Liver Metastasis: Early Experience with the Cyberknife Robotic Radio-Surgery System

Background: The liver is a common site for malignant metastases. Surgical metastatic resection, ablative therapies, and external beam radiation therapy (EBRT) all have advantages and limitations. Preliminary reports reveal SBRT treats hepatic metastases with limited toxicities. We reviewed our institution’s SBRT experience for the treatment of liver metastases to assess toxicity and outcomes.Methods: Hepatic metastases treated with SBRT were retrospectively reviewed from 2008-2010. Computed tomography (CT) identified tumor volume prior to SBRT, local recurrence and out-of-field progression after SBRT. Study endpoints were local recurrence, toxicity, and overall survival.Results: Thirty-three patients had 37 liver metastases treated with a median SBRT dose of 30Gy. Median follow-up was 8.1 months. Five lesions (13.5%) locally recurred after a median of 10.6 months. Seventeen patients had out-of-field progression (15 liver, 6 systemic) after a median of 5.1 months. Overall 23.5-month survival was 45.5%. Five patients reported nausea and seven reported pain after SBRT. There were no grade 4-5 toxicities or cases of liver failure.Conclusion: SBRT is safe and well tolerated in patients with hepatic metastases. SBRT offers a local therapy with limited toxicities to patients with lesions not amenable to traditional ablative, surgical, or regional therapies