Liver metastases are detected in 40-50% of patients diagnosed with colorectal cancer. Local treatments like surgical resection or radiofrequency ablation result in 5-year survival of 35%. However, relapse still occurs in 70% of patients. Stereotactic body radiotherapy (SBRT) has emerged as a valid treatment not only to provide excellent symptom palliation, but also is effective in local control of metastatic lesions and improves survival. The potential efficacy of SBRT as adjuvant radiotherapy in CRLM patients after surgical resection or radiofrequency ablation is still unknown.