A Retrospective Study of Stage I to IIIa Lung Adenocarcinoma After Resection: What Is the Optimal Adjuvant Modality for Patients With an EGFR Mutation?

UNLABELLED: We retrospectively reviewed a total of 257 stage I to IIIa lung adenocarcinoma after resection, tested them for the epidermal growth factor receptor (EGFR) mutation, and analyzed the effect of perioperative treatment on survival. The results showed that in patients with an EGFR mutation, adjuvant EGFR-tyrosine kinase inhibitor monotherapy after complete resection significantly prolongs disease-free survival compared with adjuvant chemotherapy and/or radiotherapy.

BACKGROUND: Adjuvant cisplatin-based chemotherapy improves non-small-cell lung cancer (NSCLC) 5-year survival rates after resection. However, adjuvant epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) efficacy and the optimal adjuvant treatment are unclear.

PATIENTS AND METHODS: The clinical records of patients tested for EGFR mutation after complete NSCLC resection were reviewed and tested for significance; EGFR mutation and adjuvant therapy effects on survival were assessed using univariate and Cox regression analyses.

RESULTS: We enrolled 257 patients (stage I, 126; stage II-IIIa, 131); 138 had EGFR mutation. EGFR mutation status was unrelated to recurrence (hazard ratio [HR], 0.83; 95% confidence interval [CI], 0.572-1.204; P = .326) or death (HR, 0.679; 95% CI, 0.406-1.136; P = .14). Thirty-one patients with EGFR mutation received adjuvant EGFR-TKIs; most (87.1%) received EGFR-TKI monotherapy. Patients who received adjuvant EGFR-TKIs had longer disease-free survival (DFS) than those who did not (P = .033) or received conventional adjuvant chemotherapy (P = .038). Adjuvant EGFR-TKIs did not affect overall survival (OS; P = .258), although the recipients had better 3-year OS (92.5% vs. 81%). Eight patients who received adjuvant EGFR-TKI developed disease recurrence, which occurred in 7 patients during adjuvant treatment. In the adjuvant EGFR-TKI group patients with a primary tumor EGFR mutation, EGFR mutation in the corresponding metastatic lymph nodes did not affect DFS, but patients who received EGFR-TKI after recurrence had longer progression-free survival (P = .087).

CONCLUSION: In patients with an EGFR mutation, adjuvant EGFR-TKI monotherapy after complete resection significantly prolongs DFS compared with adjuvant chemotherapy and/or radiotherapy.