Epidermal growth factor receptor mutation subtype has differential effects on adjuvant chemotherapy for resected adenocarcinoma pathological stages II-III.

The aim of the present study was to investigate epidermal growth factor receptor () mutations as a prognostic factor for postoperative patients with positive mutations treated with postoperative platinum-based adjuvant chemotherapy (PBAC), and whether two common mutations exhibit different responses to PBAC. A total of 110 patients who underwent complete surgical resection were enrolled, and overall survival (OS) and disease-free survival (DFS) were investigated based on mutation status and PBAC. The 3 year OS rate in patient groups were as follows: Patients with mutations (MT) undergoing PBAC, 89.3%; MT patients without PBAC, 83.3%; wild-type (WT) patients with PBAC, 82.3%; and WT patients without PBAC, 62.2%. Statistically significant differences were observed between WT patients based on PBAC (P=0.026). No statistically significant differences were observed between MT patients with PBAC and MT patients without PBAC. On the basis of mutation subtypes, the 3 year OS rate of patient groups were as follows: Patients with in-frame deletions in exon19 (19 del) with PBAC, 92.3%; patients with 19 del without PBAC, 85.7%; patients with the point mutation L858R inexon21 (21L858R) with PBAC, 86.7%; and patients with 21L858R without PBAC, 81.5%; the respective 3-year DFS rates were 53.8, 14.3, 40.2 and 26.9%. Statistically significant differences were observed in the DFS rates in 19 del patients, which was dependent on PBAC (P=0.040). mutation-positive patients exhibited a decreased benefit from PBAC for increasing in survival rate compared with WT patients. It may be necessary to consider postoperative strategies based on mutations and their subtype in the future.