Retrospective Analysis of the Incidence of Drug-Induced Interstitial Lung Disease by Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors and Survival in Patients Aged 75 Years or Older with Lung Cancer

INTRODUCTION: To date, the appropriate epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) for patients aged ≥75 years with advanced EGFR mutation-positive, nonsmall cell lung cancer remain unknown. METHODS: This study included a total of 89 patients aged ≥75 years who were diagnosed with EGFR mutation-positive, nonsmall cell lung cancer and treated with EGFR-TKIs at the Tokyo Metropolitan Geriatric Hospital and Nihon University ITABASHI Hospital from 2009 to 2020. The patients were classified into five groups based on their treatment: gefitinib (n = 23), erlotinib (n = 4), afatinib (n = 3), first-line osimertinib (n = 23), and TKI to TKI (n = 36). The efficacy and safety of each EGFR-TKI were analyzed. RESULTS: No significant differences in the overall survival and progression-free survival were observed among the groups. However, a significantly higher incidence of drug-induced interstitial lung disease (ILD) was detected with osimertinib than with the first-generation EGFR-TKIs (p = 0.008). CONCLUSIONS: In older patients with EGFR mutation-positive lung cancer, the incidence of drug-induced ILD was significantly increased during osimertinib treatment. This outcome should be noted when treating older patients with osimertinib who may not always want to live longer but want to live better.