Efficacy of Platinum-Based Adjuvant Chemotherapy on Prognosis of Pathological Stage II/III Lung Adenocarcinoma based on EGFR Mutation Status: A Propensity Score Matching Analysis

Objective This study aimed to retrospectively evaluate the efficacy of platinum-based adjuvant chemotherapy (PBAC) for patients with pathological II/III pulmonary adenocarcinoma after curative resection based on epidermal growth factor receptor (EGFR) mutation status using propensity score matching (PSM) analysis. Methods Among the 304 patients who underwent curative resection of the lung for pathological II/III pulmonary adenocarcinoma from 2002 to 2016 at the Kanagawa Cancer Center, 176 and 128 patients were wild-type EGFR (Wt) and mutant EGFR (Mt), respectively. Seventy-one Wt patients (40.3%) and 60 Mt patients (46.9%) received PBAC. The prognoses of Wt and Mt patients who did and did not receive PBAC were compared using PSM analysis to reduce bias. Results The overall survival (OS) of both Wt and Mt patients who received PBAC was significantly better than that of patients who did not receive PBAC before PSM. By multivariate analysis, PBAC was an independent prognostic factor for OS among Wt patients, as were age, carcinoembryonic antigen (CEA) level, pleural invasion, and lymph node metastasis. Although age and CEA level were independent factors for OS among Mt patients, PBAC was not a prognostic factor. After PSM, Wt patients who received PBAC had better OS than those who did not, although Mt patients who did and did not receive PBAC had no difference in OS. Conclusions PBAC was associated with favorable prognosis after curative resection among Wt patients, but not among Mt patients. PBAC might not be necessary for Mt patients with pathological stage II/III pulmonary adenocarcinoma.