KRAS and metastatic colorectal cancer: A retrospective analysis of rat sarcoma viral oncogene (RAS) wild-type metastatic colorectal cancer patients from Cetuximab Combined With Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer (CRYSTAL) and FOLFIRI Plus Cetuximab Versus FOLFIRI Plus Bevacizumab as First-Line Treatment of KRAS Wild-Type Metastatic Colorectal Cancer (FIRE-3) reported left-sided cancers to have a better prognosis in terms of survival and response rates, irrespective of treatment [25].