EGFR and neoplasm: For right-sided tumours a significant PFS and OS benefit was observed for CMS4 tumours when anti-EGFR was added to irinotecan as second line chemotherapy for both PFS (HR 0.17, 95% CI 0.04–0.71, P = 0.02) and OS (HR 0.20, 95% CI 0.05–0.83, P = 0.03) (Fig. 4 and Supplementary Fig. 1C).