Clinical significance of primary tumour location in colorectal cancer — a review

Abstract

Colorectal cancer (CRC) is one of the most common malignant neoplasms worldwide. The heterogeneous course\xa0of disease, as well as, genetic and molecular differences between tumours localized in different parts of the large\xa0intestine, resulted in an attempt to evaluate the significance of the primary tumour location and divide colorectal\xa0cancer into right- and left-sided. The results of the retrospective analyses of the phase III studies indicate that\xa0the right-sided location is a negative prognostic factor in stage IV and III of disease. The benefit of adding an\xa0anti-EGFR antibody to the first-line palliative chemotherapy was clearly demonstrated for patients with primary\xa0tumour located on the left side and the effect of treatment seems to be better than anti-VEGF therapy combined\xa0with chemotherapy. Treatement results of patients with right-sided primary tumour location are worse regardless\xa0of the type of treatment. In patients with right-sided cancer, it seems that bevacizumab treatment might be\xa0more beneficial in comparison with anti-EGFR therapy, although these suggestions are based on small groups\xa0of patients. The efficacy of bevacizumab seems to be independent of primary tumour location. It is still unclear\xa0whether the primary tumour location should be considered as an independent prognostic or predictive factor,\xa0or rather it is necessary to look for specific genetic and molecular disorders responsible for demonstrated and\xa0possible differences.