Antineoplastic Combined Chemotherapy Protocols/therapeutic use; Biomarkers, Tumor/analysis; Colorectal Neoplasms/blood; Liver Neoplasms/blood; Neoplastic Cells, Circulating/pathology; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized/administration & dosage; Bevacizumab; Camptothecin/administration & dosage; Camptothecin/analogs & derivatives; Capecitabine; Cetuximab; Colorectal Neoplasms/drug therapy; Colorectal Neoplasms/mortality; Colorectal Neoplasms/pathology; Deoxycytidine/administration & dosage; Deoxycytidine/analogs & derivatives; Epithelial-Mesenchymal Transition; Female; Fluorouracil/administration & dosage; Fluorouracil/analogs & derivatives; Follow-Up Studies; Humans; Irinotecan; Liver Neoplasms/drug therapy; Liver Neoplasms/mortality; Liver Neoplasms/secondary; Male; Middle Aged; Neoplasm Staging; Organoplatinum Compounds/administration & dosage; Oxaliplatin; Prognosis; Survival Rate

biomarkers; circulating tumor cells; epithelial to mesenchymal transition; metastatic colorectal cancer; patient outcome; therapy response