Epidermal Growth Factor Receptor Mutations and Prognosis in Pathologic N1-N2 Pulmonary Adenocarcinoma

Advanced unresectable pulmonary adenocarcinoma with the epidermal growth factor receptor (EGFR) exon 21 L858R point mutation (Ex21) is associated with a poor prognosis. However, for early-stage resectable adenocarcinoma, Ex21 tumors have a lower-grade malignancy than exon 19 deleted (Ex19) tumors. We therefore investigated the effect of EGFR mutations on the prognosis in patients with completely resected pN1-N2 adenocarcinoma.

Five-year disease-free survival (DFS) and overall survival (OS) were analyzed in 202 pN1-N2 pulmonary adenocarcinoma patients, 100 of whom had EGFR mutations, comprising Ex21 in 41 (20.3%), Ex19 in 55 (27.2%), and Ex18 in 4 (2%).

Patients with and without EGFR mutations had similar DFS (26.2% vs 24.6%, respectively; p = 0.280) and OS (64.9% vs 54.2%, respectively; p = 0.564). Patients with Ex19 tumors had significantly better DFS (38.8% vs 11.8%, p = 0.001) and tended to have better OS (78.3% vs 48.3%, p = 0.123) than those with Ex21 tumors. For pN1, patients with Ex19 tumors had a longer disease-free interval (54.0 vs 22.3 months, p = 0.003) and median survival time (81.0 vs 50.6 months, p = 0.022) than those with Ex21 tumors. For pN2, patients with Ex19 tumors had longer disease-free interval than those with Ex21 tumors (43.6 vs 30.1 months, p = 0.109). Multivariate analysis showed Ex21 was a prognosticator of poor DFS (hazard ratio, 2.25; 95% confidence interval, 1.21 to 4.20).

For pN1-N2 pulmonary adenocarcinoma, Ex21 mutation was associated with poorer prognosis than Ex19 mutation. Thus, EGFR mutation status should be considered when predicting prognosis.