It is important to bear in mind that since 2015, recommendations for treatment of mCRC patients have included that EGFR inhibitors should not be administered in cases of NRAS-mutated tumours.18 However as this had not yet been formally implemented at the time of patient accrual during the current study (2009–2012), NRAS-mutated patients were included and treated. Here, NRAS is linked to neoplasm.