Adenocarcinoma Harboring EGFR-RAD51 Fusion Treated With Osimertinib: A Case Report.

EGFR mutations are among the most common driver mutations in lung adenocarcinoma. Rare alterations, such as the EGFR-RAD51 fusion, respond to treatment with EGFR tyrosine kinase inhibitors but can be missed by limited genomic sequencing panels. Here, we report a case of metastatic lung adenocarcinoma in a never-smoker patient who initially did not have a targetable alteration identified on two different sequencing panels. The initial response to combination chemoimmunotherapy was short-lived. A rare EGFR-RAD51 fusion was then identified using a more in-depth sequencing panel. The patient experienced a dramatic and durable response to osimertinib. This case highlights the rarity of EGFR-RAD51 fusions, the efficacy of EGFR tyrosine kinase inhibitors, and the importance of a thorough search for targetable alterations in never-smokers with lung adenocarcinoma.