The impact of epidermal growth factor receptor mutation status on adjuvant chemotherapy for patients with high-risk stage I lung adenocarcinoma

The aim of this study was to evaluate the role and effect of adjuvant chemotherapy based on epidermal growth factor receptor mutation status in patients with stage I lung adenocarcinoma.Between 2010 and 2016, of 1901 patients with pathologic stage I (8th edition) non-small cell lung cancer, we identified 475 with high-risk (pT1c/T2a or positive for lymphovascular invasion) stage I lung adenocarcinoma who underwent lobectomy. We estimated propensity scores to adjust for confounding variables, including age, sex, Brinkman index, pulmonary functions, comorbidities, surgical approach, invasive component tumor size, visceral pleural, lymphatic, and vascular invasion, adenocarcinoma subtype, epidermal growth factor receptor mutation status, postoperative complications, and institution associated with the administration of adjuvant chemotherapy. The primary end point was recurrence-free survival.Of 292 patients without/unknown epidermal growth factor receptor mutation, 105 (36.0%) received adjuvant chemotherapy and 187 (64.0%) did not. In 69 pairs of patients who were propensity score matched, the 5-year recurrence-free survival was significantly better in those who underwent adjuvant chemotherapy (88.4%) than in those who did not (63.6%; P = .001). Of 183 patients with epidermal growth factor receptor mutation, 78 (42.6%) received adjuvant chemotherapy and 105 (57.4%) did not. In 49 pairs of propensity score-matched patients, there was no significant difference in the 5-year recurrence-free survival between those who underwent adjuvant chemotherapy (74.3%) and those who did not (80.5%; P = .573).The effect of adjuvant chemotherapy for high-risk stage I lung adenocarcinoma varied by epidermal growth factor receptor mutation status. Epidermal growth factor receptor mutation status may help to identify patients with high-risk stage I lung adenocarcinoma who may benefit from adjuvant chemotherapy.