Radiosensitization of AVASTIN (Bevacizumab) With Stereotactic Body Radiotherapy for Colorectal Liver Metastasis

This is a single-centre, single-arm open-label proof-of-concept study to analyze the imaging (DCE-CT,CEUS and Quantitative US) effects of neoadjuvant bevacizumab and SBRT on colorectal metastases to the liver. Patients will receive 2 doses of bevacizumab 5mg/kg IV prior to SBRT. The second dose of bevacizumab will be given 2 weeks after the first dose of bevacizumab and within 48 hours of starting the first dose of SBRT. The SBRT prescription dose will be up to 60 Gy in 6 fractions, delivered on alternating weekdays for 2 weeks. Total SBRT dose will be determined by size of target lesion, liver sparing and organs-at-risk dose constraints. DCE-CT, CEUS and Quantitative US will be performed within 7 days prior to the first dose of bevacizumab, after the second dose of bevacizumab and within 7 days of completing SBRT.