Response to anti-EGFR therapy in chemo-refractory right-sided RAS wild-type metastatic colorectal cancer: a case report and literature review

Treatment options for right-sided RAS-WT metastatic CRC are limited, particularly after progression on standard chemotherapies. While anti-EGFR antibodies have demonstrated detrimental survival impact in the first-line setting for right-sided CRC, their performance in later lines is less well-characterized. This case challenges the notion of right-sided disease as uniformly resistant to EGFR inhibition and highlights the need for additional biomarker studies to identify the subset of right-sided CRC that may benefit from EGFR targeted strategies. Emerging evidence suggests that more stringent genomic criteria for EGFR resistance, beyond RAS mutation status alone, may refine patient selection for benefit from anti-EGFR therapies.