Impact of the IASLC Grading and Other Pathological Features on Relapse and Survival in Completely Resected Lung Adenocarcinoma by EGFR Mutation Status: A Supplementary Analysis of the CReGYT‐01 EGFR Study

This study aimed to clarify the risk factors for recurrence in epidermal growth factor receptor (EGFR) mutated and wild-type lung adenocarcinomas, with a focus on the newly proposed International Association for the Study of Lung Cancer (IASLC) grading system. We enrolled 2106 patients who underwent complete anatomical radical resection and had a known EGFR mutational status and IASLC grade. Patient characteristics and pathological features were analyzed to assess the cumulative incidence of recurrence (CIR). No significant differences were found in the CIR between the EGFR mutated (EGFRm) and wild-type groups. In the EGFRm group, multivariate analysis identified IASLC grade 2, grade 3 (reference: grade 1), pathological stage II/III, lymphatic invasion (ly), vessel invasion (v), and plural invasion as independent risk factors for recurrence. In the wild-type group, IASLC grades 2 and 3, pathological stage II/III, ly, and v were identified as independent risk factors for recurrence. Patients with any independent risk factor had a significantly poorer overall survival and a higher CIR compared with those without a risk factor in both the EGFRm and wild-type groups. The IASLC grading system is a valuable prognostic factor for recurrence in patients with lung adenocarcinoma harboring EGFRm.