A comprehensive clinical trajectory of EGFR A763_Y764insFQEA-positive non-small cell lung cancer treated with fifth-line osimertinib following circulating tumor DNA-based detection: a case report

This case highlights the diagnostic and therapeutic significance of liquid biopsy in detecting rare but actionable <i>EGFR</i> variants. The A763_Y764insFQEA mutation is uniquely sensitive to EGFR-TKIs, and comprehensive molecular testing can guide effective targeted therapy even in later treatment lines. Broader implementation of hybrid-capture-based assays may improve precision oncology outcomes for patients with rare <i>EGFR</i> alterations.