Gefitinib Versus Adjuvant Chemotherapy in Patients With Stage II-IIIA Non-Small-Cell Lung Cancer Harboring Positive EGFR Mutations: A Single-Center Retrospective Study.

Background: The superior efficacy of first-line treatment with gefitinib over that of standard chemotherapy was demonstrated in patients with advanced non-small-cell lung cancer (NSCLC) harboring sensitive mutation of epidermal growth factor receptor (EGFR). However, scarce evidence showing the superiority of gefitinib to chemotherapy exists regarding the postoperative adjuvant therapy of EGFR mutation-positive patients with stage II-IIIA NSCLC. To address this important gap, we undertook a retrospective study to assess the efficacy of adjuvant gefitinib versus adjuvant chemotherapy (AC) in patients with completely resected EGFR-mutant stage II-IIIA NSCLC.

Patients And Methods: A total of 116 patients with completely resected II-IIIA NSCLC and confirmed positive EGFR mutation (exon 19 deletion or exon 21 Leu858Arg) between January 2013 and March 2017 were included in our study. Disease-free survival (DFS) was analyzed in 55 patients treated with gefitinib and 61 patients treated with a platinum-based 2-drug-combination AC. Propensity score matching allowed the generation of best matched pairs for the 2 categories (1:1 ratio). Factors affecting survival were assessed by the Kaplan-Meier method and Cox regression analysis.

Results: The matched cohort consisted of 52 gefitinib and 52 AC patients with a median follow-up of 37.1 and 31.5 months, respectively. DFS was significantly longer in the gefitinib group than that in the AC group (34.9 months [95% confidence interval (CI), 21.1-48.7] versus 19.3 months [95% CI, 13.3-25.3]; hazard ratio = 0.36 [95% CI, 0.19-0.68], log-rank P = .001). In the gefitinib group the most common adverse events (AEs) were rash (76.9%), aminotransferase elevation (53.8%), and diarrhea (46.2%), whereas in the AC group the most common AEs were neutropenia (67.3%), nausea or vomiting (63.5%), and anemia (44.2%). Less frequent grade 3 or higher AEs were observed in the gefitinib group (15.4% vs. 38.5% in the AC group). After receiving gefitinib for 3 months, one patient was diagnosed with interstitial lung disease, which was regarded as the most severe treatment-related AE. No deaths were treatment related.

Conclusion: In this retrospective study, compared to AC, gefitinib provided a statistically significant DFS benefit, reduced toxicity in EGFR mutation-positive patients with resected II-IIIA NSCLC. These results require further validation by prospective randomized trials.