Severe Drug-Induced Interstitial Lung Disease After Administration of Osimertinib as Adjuvant Treatment for Resected EGFR-Mutated NSCLC: A Case Report

Osimertinib administration has been approved as an adjuvant treatment after complete surgical resection in patients with EGFR-mutated NSCLC. This article presents the first report of life-threatening postoperative osimertinib-induced interstitial lung disease. An 83-year-old male patient underwent right upper lobectomy (pathologic stage IIA) and osimertinib (80 mg/d) was initiated on postoperative day 75. On day 44 of osimertinib administration, chest computed tomography revealed diffuse ground-glass opacities; accordingly, osimertinib-induced interstitial lung disease was diagnosed. Steroid pulse therapy was initiated using a high-flow nasal cannula to treat dyspnea and hypoxemia, rapidly improving the respiratory status and imaging findings; moreover, the patient's clinical course was excellent. This case report suggests that the postoperative occurrence of severe osimertinib-induced interstitial lung disease is a crucial factor that must be considered in patient decision-making regarding perioperative treatment.