Abstract
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) have become the first choice for patients with sensitive mutations and have significantly improved prognosis. EGFR exon 19 deletions and L858R mutation in exon 21 are the most common sensitive mutations in lung adenocarcinoma. With advances in detection technology, some rare variants of EGFR have been detected, including EGFR kinase domain duplications and EGFR fusions. Only a few reports have revealed the effectiveness of EGFR-TKIs in patients with these rare variants. In this study, we report a case of EGFR-RAD51 fusion in lung adenocarcinoma that showed a response to icotinib; these findings provide additional support for the use of EGFR-TKIs for patients with these atypical variants. KEY POINTS: A young patient with lung adenocarcinoma harboring a rare EGFR-RAD51 fusion who responded to icotinib with a PFS of longer than 15 months.All reported EGFR-RAD51 fusions have the same breakpoints and show responses to EGFR-TKIs including icotinib, except for one patient who responded to chemotherapy.Although EGFR fusion is a rare EGFR variant type, the efficacy of EGFR-TKIs suggests the necessity for new detection technology, such as NGS, for patients with lung adenocarcinoma.The clinical usage of NGS could maximize the benefits of precision medicine in patients with cancer.The current case provides new evidence for the efficacy of icotinib in patients with the rare EGFR-RAD51 fusion and EGFR-activating mutations.