Stereotactic body radiation therapy for liver metastasis from colorectal cancer: size matters.

PURPOSE We analysed our initial experience with SBRT in liver metastasis from colorectal cancer at our institution. MATERIALS AND METHODS Between January/2014 and December/2017, 22 patients with 31 LMCCR were treated. Local control (LC) was assessed using the Kaplan-Meier and log-rank tests. We analysed potential prognostic factors for LC: sex, PTV size, number of LM and the radiation scheme. RESULTS Median age: 69 years. Prior chemotherapy or local liver treatments: 81.8% and 63.6% of patients, respectively. SBRT consisted of 3 × 20 Gy (42.9%) and 3 × 15 Gy (31.4%). There were 88.5% responses (57.1% CR and 31.4% PR). Median follow-up was 30 months. LC per lesion at 12 and 24 months was 85.3% and 61.8%, respectively. Tumour volumes > 30 cc correlated with worsened 2-year-control rates (90% vs 34.5%) (p = 0.005). There was only a patient with CTC-grade 3 toxicity. CONCLUSIONS Liver SBRT is a safe and effective treatment that achieves high local control rates. We found a significant correlation between larger LMCRC and worse local control.