Prognostic and predictive markers in liver limited stage IV colorectal cancer.

Colorectal cancer is the third most commonly diagnosed cancer among both men and women. Personalised treatment options remain complex, although there is broad agreement over which patients with colorectal liver metastases (CRLM) should and should not be offered resection. Decisions on an optimal management strategy involves careful assessment of both technical and oncological factors. In this review we aim to summarise current prognostic biomarkers for metastatic colorectal cancers, specifically patients considered for resection. A number of clinico-pathological factors have been identified as prognostically important with good internal validity, but limited external validity. Furthermore, these prognostic scoring systems do not take factor in modern chemotherapeutic agents and the disease modification these agents produce. Histopathological response to chemotherapy is of significant prognostic importance. Molecular markers can help predict the efficacy of a biological agent. An important prognostic factor of liver metastasis is the recognition that location of the primary colorectal cancer impacts on metastatic phenotype and represents difference in genotype, i.e. proximal tumours are more aggressive than distal tumours with an increased likelihood of disease progression. Several mutational molecular markers identified include microsatellite instability, BRAF, and KRAS/NRAS and combination mutations, which confer poorer outcomes. Accurate prognostication in patients with liver limited colorectal metastases remains crucial, as this allows tailoring treatment options to each disease and improving outcomes. Access to tissue before treatment remains a limitation although advances in ability to assess tumour biology by non-invasive methods are promising. Crown