Stage III EGFR exon 19-deleted lung adenocarcinoma: osimertinib and surgery

What happened, in summary

A 59-year-old former smoker was diagnosed after routine imaging in September 2021 found a 3.7 cm lesion in the left lung. PET-CT showed high FDG uptake in the left upper lobe and moderate uptake in both ipsilateral and contralateral mediastinal lymph nodes, with no distant metastasis. Brain MRI showed no intracranial metastasis. CT-guided biopsy confirmed lung adenocarcinoma, and tissue next-generation sequencing found an EGFR exon 19 deletion. Her disease was classified as T2aN2M0, within Stage III disease as reported in the case. She started neoadjuvant osimertinib 80 mg daily for 12 weeks. PET-CT then showed a radiological complete response. In February 2022, she underwent resection of the left upper lobe, and pathology confirmed a complete response. She continued adjuvant osimertinib after surgery. After 24 months of follow-up, PET-CT and brain MRI showed no sign of metastasis. Her course was driven by EGFR exon 19-deleted lung adenocarcinoma rather than mixed lung-cancer histology. Osimertinib was used before surgery to achieve radiologic complete response and then continued afterward as adjuvant therapy. No chemotherapy, immunotherapy, or distant metastatic site was described. The latest status is best represented as no sign of metastasis after treatment. PET-CT showed radiologic complete response before surgery, and the surgical specimen later confirmed pathologic complete response. She continued osimertinib after surgery as part of the reported plan. The stage and outcome should therefore be interpreted together: Stage III at diagnosis, complete response after neoadjuvant therapy and surgery, and no metastatic disease on follow-up imaging.