Drug-induced interstitial lung disease caused by gefitinib in the treatment of non-small cell lung cancer: A case report.

Gefitinib, a first-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), is widely used in treating non-small cell lung cancer (NSCLC) with EGFR mutations. Although effective, gefitinib is associated with rare but life-threatening interstitial lung disease (ILD). In the present study, a 68-year-old male with stage IIIB lung adenocarcinoma was reported, who developed acute interstitial pneumonia 20 days after initiating gefitinib therapy. The patient presented with high fever (41˚C), dyspnea and hypoxemia. Chest CT revealed bilateral diffuse interstitial infiltrates and pleural effusion. After excluding infectious and cardiac etiologies, gefitinib-induced ILD was diagnosed. Immediate discontinuation of gefitinib, combined with high-dose glucocorticoids (methylprednisolone 80 mg/day) and oxygen therapy, led to clinical improvement. However, ILD recurred upon rechallenge with the original gefitinib dose. This case highlights the importance of early recognition and prompt management of EGFR-TKI-related ILD. The challenges of rechallenging EGFR-TKIs post-recovery was further discussed and the need for personalized risk-benefit assessments was emphasized.