# A Case of Lung Adenocarcinoma With Concurrent EGFR Mutation and ALK Fusion Combined With Literature Review

## TL;DR

A patient with lung cancer had both EGFR mutation and ALK fusion, showing the need for retesting and switching treatments for better outcomes.

## Contribution

Highlights the clinical benefit of retesting for co-occurring genetic alterations in lung adenocarcinoma patients.

## Key findings

- Retesting for EML4-ALK fusion in EGFR-mutant patients can reveal resistant mechanisms.
- Switching to alectinib after identifying ALK fusion leads to rapid clinical improvement.
- Co-occurring genetic alterations may be missed initially but are critical for treatment decisions.

## Abstract

This case underscores the critical importance of retesting for resistant mechanisms, such as EML4‐ALK fusion, in patients with EGFR‐mutant lung adenocarcinoma who experience rapid progression on EGFR‐tyrosine kinase inhibitor (TKI) therapy. Early identification of such co‐alterations and an immediate switch to alectinib can lead to rapid and sustained clinical improvement.