Prognostic impact of EGFR mutations in T1-4N0M0 lung adenocarcinoma: analyses focus on imaging and pathological features

Background: With the development of tyrosine kinase inhibitor (TKI) treatment, the prognosis of advanced lung adenocarcinoma (LUAD) patients with epidermal growth factor receptor (EGFR) mutations has been continuously improving. This study aims to propose the utilization of pathological characteristics and imaging features to evaluate the impact of EGFR gene mutations on the prognosis of T1-4N0M0 LUAD.

Methods: Among the cases diagnosed with LUAD between April 2015 and April 2016, 438 patients with T1-4N0M0 LUAD were included, and the clinical characteristics were collected. EGFR mutations were analyzed in these patients who underwent lobectomy with different radiological and pathological types for the relation to patient prognosis.

Results: Patients with EGFR mutation had longer recurrence-free survival (RFS) in part-solid nodules cohort (P=0.03), which was in contrast to purely solid nodules (P=0.06). Positive EGFR mutations significantly prolonged RFS in nodules consolidation-to-tumor ratio (CTR) values of 0-0.5. In the International Association for the Study of Lung Cancer (IASLC) grade I patients with EGFR mutations, there was a trend towards longer RFS but with no effect on overall survival (OS) (P=0.08; P=0.71); in IASLC grade II patients with EGFR mutations, there was a tendency of longer OS (P=0.06); in IASLC grade III patients with EGFR mutations, both RFS and OS were significantly shorter (P=0.02; P=0.005). EGFR mutation state was not an independent risk factors for both RFS and OS.

Conclusions: EGFR mutations are associated with a favorable prognosis in nodules with lower IASLC grading or more ground glass opacity (GGO) components. The results were reversed in patients with higher IASLC grading or no GGO component.