Inclusion Criteria:

- Colorectal adenocarcinoma stage IV patients.

- ECOG= 0-1

- Age > 18 years.

- Fit to receive chemotherapy treatment

- Availability of tumor tissue or possibility of a tumor biopsy to determine
therapeutic targets.

- Adequate renal (Cr < 1,5 mg/d), liver (bilirubin≤1,5 mg/dl, AST and ALT ≤ 3.0 x the
upper limit of normal) and normal bone marrow function ( absolute neutrophil count ≥
1500/µl, hemoglobin ≥ 9.0g/dl and a platelet count of ≥ 100.000/µl)

Exclusion Criteria:

- Contraindication for the administration of any of the drugs used in the study
including capecitabine, irinotecan, oxaliplatin, cetuximab or bevacizumab.

- Previous Chemotherapy treatment