In resectable colorectal liver
metastasis (CRLM) the role and use of molecular
biomarkers is still controversial. Several
biomarkers have been linked to clinical outcomes in CRLM, but none have so far become routine for clinical decision making. For several reasons, the clinical risk score appears to no longer hold the same predictive value. Some of the reasons include the ever expanding indications for liver resection, which now increasingly tend to involve extrahepatic disease, such as lung
metastases (both resectable and non-resectable) and the shift in indication from "what is taken out" (e.g., how much liver has to be resected) to "what is left behind" (that is, how much functional liver tissue the patient has after resection). The latter is amenable to modifications by using adjunct techniques of portal vein embolization and the associating liver partition and portal vein
ligation for staged
hepatectomy techniques to expand indications for liver resection. Added to this complexity is the increasing number of molecular markers, which appear to hold important prognostic and predictive information, for which some will be discussed here. Beyond characteristics of tissue-based genomic profiles will be liquid biopsies derived from
circulating tumor cells and cell-free
circulating tumor DNA in the blood. These markers are present in the peripheral circulation in the majority of patients with metastatic
cancer disease. Circulating
biomarkers may represent more readily available methods to monitor, characterize and predict
cancer biology with future implications for
cancer care.