Proton stereotactic body radiation therapy for liver metastases—results of 5-year experience for 81 hepatic lesions

Abstract

Background: To report on our institutional experience using Proton stereotactic body radiation therapy (SBRT) for patients with liver metastases.Methods: All patients with liver metastases treated with Proton SBRT between September 2012 and December 2017 were retrospectively analyzed. Local control (LC) and overall survival (OS) were estimated using the Kaplan-Meier method calculated from the time of completion of Proton SBRT. LC was defined according to Response Evaluation Criteria in Solid Tumors (RECIST) guidelines (version 1.1). Toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.Results: Forty-six patients with 81 lesions were treated with Proton SBRT. The median age was 65.5 years old (range, 33-86 years) and the median follow up was 15 months (range, 1-54 months). The median size of the gross tumor volume (GTV) was 2.5 cm (range, 0.7-8.9 cm). Two or more lesions were treated in 56.5% of patients, with one patient receiving treatment to a total of five lesions. There were 37 lesions treated with a biologically effective dose (BED) ≤60, 9 lesions with a BED of 61-80, 22 lesions with a BED of 81-100, and 13 lesions with a BED >100. The 1-year and 2-year LC for all lesions was 92.5% (95% CI, 82.7% to 96.8%). The grade 1 and grade 2 toxicity rates were 37% and 6.5%, respectively. There were no grade 3 or higher toxicities and no cases of radiation-induced liver disease (RILD).Conclusions: Proton SBRT for the treatment of liver metastases has promising LC rates with the ability to safely treat multiple liver metastases. Accrual continues for our phase II trial treating liver metastases with Proton SBRT to 60 GyE (Gray equivalent) in 3 fractions.

American Radium Society Appropriate Use Criteria for the use of liver‐directed therapies for nonsurgical management of liver metastases: Systematic review and guidelines

“…PBT can add to the safety of liver irradiation, particularly in the setting of multiple LM, and Coffman et al. demonstrated no cases of RILD in 46 patients treated to 81 LM while achieving an LC of 92% 69 …”

Do We Have a Winner? Advocating for SBRT in HCC Management

“…Protons can be used to reduce the integral liver dose associated with photon SBRT, potentially minimizing the risk of hepatic toxicity associated with radiotherapy [41] . A retrospective single-institutional review of stereotactic body proton therapy (SBPT) for 81 liver metastases in 46 patients, 56.5 % of whom had two or more treated tumors, reported no grade 3 + toxicities [42] . Conformality and toxicity of SBPT with passive-scatter technology may be further improved by utilizing modern radiotherapy techniques for planning (e.g.…”

Local Control Following Stereotactic Body Radiation Therapy for Liver Oligometastases: Lessons from a Quarter Century

“…It is important to note that there are limited randomized data comparing SBRT to other local modalities for the treatment of liver metastases. Several retrospective and prospective studies reported favorable LC rates following SBRT for limited liver metastases [2,15,[20][21][22][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Table 1 summarizes key retrospective and prospective studies published in the last two decades.…”