Impact of Smoking History on the Efficacy of Gefitinib in Patients with Non-Small Cell Lung Cancer Harboring Activating Epidermal Growth Factor Receptor Mutations.

ABSTRACT

BACKGROUND: Gefitinib treatment has come to be recognized as the standard therapy for patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. However, resistance to gefitinib has been observed in certain subpopulations of these patients. The purpose of this study was to evaluate the impact of smoking status on the efficacy of gefitinib in patients with NSCLC harboring EGFR mutations. METHODS: The records of NSCLC patients harboring EGFR mutations who were treated with gefitinib at Kitasato University Hospital were retrospectively reviewed, and the treatment outcomes were evaluated. RESULTS: In 153 patients with NSCLC harboring EGFR mutations, the overall response rate and progression-free survival (PFS) were 66.7% and 9.0 months, respectively. PFS differed significantly among the current smokers and never-smokers/former light smokers (10.7 vs. 5.4 months, p=0.0002), and the response rate was significantly higher in the never-smokers/former light smokers than in the current smokers (72.3 vs. 55.8%, p=0.04). Multivariate analysis identified smoking status as an independent predictor of PFS. CONCLUSION: The clinical data obtained in this study provide a valuable rationale for considering smoking status as a predictor of the efficacy of gefitinib in patients with NSCLC harboring activating EGFR mutations.