The choice of the biological agent in front-line therapy had a statistically significant impact on median OS in patients with right-sided tumours (anti-epidermal growth factor receptor (EGFR): 10.6 months [95%-CI: 5.2-NA]; anti-vascular endothelial growth factor (VEGF): 26.2 months [95%-CI: 17.9-NA]; HR: 2.69 [95%-CI: 1.30–12.28]; p = 0.015) but not in patients with left-sided tumours (anti-EGFR: 37.0 months [95%-CI: 20.2–56.6]; anti-VEGF: 32.3 months [95%-CI: 23.6–41.1]; HR: 0.97 [95%-CI: 0.56–1.66]; p = 0.905). The gene discussed is EGFR; the disease is neoplasm.