Prognostic Factors for Survival After Recurrence in Patients With Completely Resected Lung Adenocarcinoma: Important Roles of Epidermal Growth Factor Receptor Mutation Status and the Current Staging System

Abstract Background The current staging system and epidermal growth factor receptor (EGFR) mutation status are key factors for predicting survival. However, the significance of these factors as predictors of survival after disease recurrence (PRS) has not been sufficiently elucidated. The objective of this study was to investigate the clinicopathological factors, particularly the EGFR mutation status and pathological stage (p-stage), which affect PRS in patients with completely resected lung adenocarcinoma. Patients and Methods We retrospectively reviewed the data of 198 consecutive lung adenocarcinoma patients with disease recurrence who previously underwent complete surgical resection in our hospital. Results Of the 198 patients, 117 were examined for EGFR mutations (mutants). Mutants were detected in 57 patients (28.7%). The patients with mutants had a significantly better 3-year PRS (3y-PRS) rate (68.6%) than those with an EGFR wild type (WT) status (51.7%) or an unknown (UN) status (27.0%). The 3y-PRS rates for p-stage I to II (p-I-II) and p-stage III (p-III) were 52.5% and 29.3%, respectively. Multivariate survival analysis showed that the EGFR mutation status and p-stage had significant associations with favorable PRS. The 3y-PRS rate for mutants/p-I-II (81.4%) was significantly better than that for mutants/p-III (48.0%). Conversely, there was no significant difference between mutants/p-III and WT/UN/p-I-II (3y-PRS: 40.7%) or between mutants/p-III and WT/UN/p-III (3y-PRS: 24.4%). Conclusion EGFR status and p-stage were shown to be essential prognostic factors for estimating PRS. In patients with mutants, those with early p-stage tumors showed better PRS than those with advanced p-stage tumors.