Stereotactic body radiotherapy (SBRT) with or without surgery for primary and metastatic liver tumors.

Abstract

360 Background: We report on the outcome and toxicity of liver SBRT alone or in combination with surgery for inoperable primary and metastatic liver tumors. Methods: Patients with up to four isolated hepatic metastases (sum of tumor diameters ≤ 8cm) and individual tumor diameter ≤ 9 cm received SBRT at 46.8Gy ± 3.7 in 4-6 fractions. In patients with hepatic cirrhosis, liver dose constraints were imposed exclusively on residual functional liver volume defined on SPECT during SBRT treatment planning. The primary end point was local control with at least 6 months of radiographic followup, and secondary end points were toxicity and survival. Results: Between 2007-2014, 120 lesions in 91 patients with either unresectable primary (n = 43) or metastatic liver cancer (n = 48) completed liver SBRT to 36-60 Gy delivered in 4 to 6 treatment fractions, with a mean BED of 197 Gy3 (range 108 – 300 Gy3). Median followup was 20.3 months (range 1.9 - 64.1). Fourteen patients underwent liver transplant with SBRT as a bridging therapy or for tumor downsizing. Eight patients completed hepatic resections in combination with planned SBRT for unresectable tumors. Two-year local control was 96% for hepatoma and 93.8% for metastases; it was 100% for lesions ≤ 4cm. Ten of 14 transplanted patients developed complete pathological response with median time to transplant of 5.7 months (range 1.7 – 23.3). No incidence of grade > 2 treatment toxicity was observed. There was no accelerated Child-Pugh class migration from A to B or from B to C. There were no operative or perioperative complications in patients who received SBRT prior to liver transplant or in combination with planned hepatectomy. Two-year overall survival was 82.3% (hepatoma) and 64.3% (metastases). Conclusions: In this retrospective analysis we demonstrate that liver SBRT alone or in combination with surgery is safe and effective for the treatment of isolated inoperable hepatic malignancies and provides excellent local control rates with minimal toxicity.