A Phase II study to assess efficacy and safety of a combination chemotheraphy in first-line treatment with Xeloda + Oxaliplatin + Avastin or Xeloda + Irinotecan + Avastin. At progression of disease (second-line treatment) patient will receive Xeloda + Oxaliplatin + Avastin when received Xeloda + Ir

Primary objectives: Determine the efficacy of modified XELIRI (Capecitabine and Irinotecan) in combination with bevacizumab followed by XELOX (Capecitabine and Oxaliplatin) in combination with bevacizumab at progression in comparison with the reverse sequence based on duration of disease control (DDC) .
Primary endpoints: The primary endpoint is to determine the efficacy of modified XELIRI (Capecitabine and Irinotecan) in combination with bevacizumab followed by XELOX (Capecitabine and Oxaliplatin) in combination with bevacizumab at progression in comparison with the reverse sequence based on DDC.