Stereotactic body radiotherapy for primary and metastatic liver tumors - the Mayo Clinic experience.

Introduction: To better understand the efficacy of liver SBRT we reviewed our prospectively collected institutional SBRT database.

Methods: Between May 2008 and March 2013, 80 patients with 104 liver lesions received SBRT. The Kaplan-Meier method estimated local control (LC), overall survival (OS). Cox proportional hazards regression models identified factors associated with LC and OS.

Results: The median follow-up for living patients was 38.6 months. Patients had primary (n=17) or metastatic (n=63) tumors. The median tumor size was 2.7 cm (range, 0.6-14.0). The 1 and 4 year rates of LC were 89.4% and 88%, respectively. Colorectal (CRC) metastasis was associated with lower rates of LC (p=0.013). OS at 1 and 4 years was 78% and 25%, respectively. Patients with CRC metastases had higher rates of OS (p=0.03). The occurrence of severe acute and late toxicity was 3.8% and 6.3%, respectively.

Conclusions: SBRT should be studied in prospective clinical trials compared with other liver-directed treatment modalities.