What happened, in summary

A 54-year-old woman who had never smoked was diagnosed with right upper-lobe lung adenocarcinoma in October 2020. She underwent an extended right upper lobectomy with mediastinal lymph-node dissection, then completed six cycles of paclitaxel plus cisplatin chemotherapy. Initial testing did not identify an EGFR mutation or ALK or ROS1 rearrangement, and PD-L1 expression was below 1%.

In May 2022, multiple brain metastases marked disease progression. She underwent whole-brain radiation and later received four cycles of carboplatin plus pemetrexed, which had to be stopped because of severe toxicity. Expanded testing in 2023 identified HER2 amplification, and trastuzumab produced clinical and radiologic disease stabilization for almost two years.

Further testing of archived tumor tissue later found an EGFR L858R mutation. When new lung metastases appeared in April 2025, treatment changed to gefitinib. The metastatic lung lesions then completely regressed. By April 2026, she remained on gefitinib with no active tumor lesions. She had lived more than five years, about 66 months, from her original lung-cancer diagnosis despite metastatic progression during the course of her disease.