Optimal Adjuvant Therapy in Resected Stage IIIA-N2 Non-Small-Cell Lung Cancer Harboring EGFR Mutations

Background: Some non-small-cell lung cancer (NSCLC) patients are unexpectedly diagnosed with stage IIIA-N2 disease at the time of thoracoscopy or thoracotomy. Because of the limited statistical evidence of induction chemotherapy for these patients, it is necessary to develop more profound treatment strategies. Methods: The demographic and clinical characteristics of patients with stage IIIA-N2 NSCLC harboring epidermal growth factor receptor (EGFR) mutations after radical resection were retrospectively reviewed. The patients were divided into 3 groups based on treatment: EGFR tyrosine kinase inhibitors (EGFR-TKIs, erlotinib or gefitinib), adjuvant chemotherapy (docetaxel plus cisplatin), and combination treatment (chemotherapy plus EGFR-TKIs). The effect of adjuvant therapy on survival rate was assessed using univariate and Cox regression analyses. Results: Patients receiving EGFR-TKIs alone showed significantly improved disease-free survival (DFS; p = 0.025) when compared to those receiving chemotherapy alone. Compared to chemotherapy alone, the combination of chemotherapy and EGFR-TKIs resulted did not significantly improve DFS (p < 0.001) and overall survival (OS p < 0.001). The combination of EGFR-TKIs with chemotherapy as adjuvant therapy led to improvements in both DFS (p = 0.116) and OS (p = 0.039) compared to patients receiving a EGFR-TKI monotherapy. Toxicities were mild in the 3 treatment groups. Conclusions: Our study demonstrated that adjuvant EGFR-TKI treatment significantly increased the DFS of patients with stage IIIA-N2 NSCLC when compared with cisplatin-based chemotherapy. The use of EGFR-TKIs and chemotherapy is recommended in the setting of combined-modality therapy.