Impact of EGFR Mutation and ALK Translocation on Recurrence Pattern After Definitive Chemoradiotherapy for Inoperable Stage III Non-squamous Non-small-cell Lung Cancer

We evaluated the failure pattern after definitive chemoradiotherapy in patients with stage III non-small-cell lung cancer harboring epidermal growth factor receptor mutations and/or anaplastic lymphoma kinase translocation. Although the epidermal growth factor receptor-mutant group showed a lower incidence of infield failure and higher incidence of out-of-field failure, the group with anaplastic lymphoma kinase translocation showed no characteristic in-field or out-of-field failure pattern. Introduction: This study was aimed at clarifying the failure pattern after definitive chemoradiotherapy in patients with stage III non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations and/or anaplastic lymphoma kinase (ALK) translocation. Methods and Materials: This retrospective study was a single-institution study conducted on patients with unresectable stage III non-squamous NSCLC treated by definitive chemoradiotherapy between January 2006 and March 2016. Only patients with information of EGFR mutations and/or ALK translocation were included. The prognosis and initial recurrence patterns were compared according to the presence/absence of EGFR mutation and/or ALK translocation. Results: A total of 173 patients (34 with activating EGFR mutations, 13 who were positive for ALK translocation) were enrolled, and the median follow-up duration was 36 months (range, 3-123 months). The 3-year overall survival rate was significantly higher in the EGFR-mutant group than in the wild-type EGFR group (75% vs. 46%; P = .002). There was a tendency towards a better overall survival in the ALK-positive group than in the ALK-negative group (68% vs. 44%; P = .085). No differences in the 3-year progression-free survival were observed according to the EGFR or ALK status. The EGFR-mutant group showed a significantly lower rate of in-field failure (P = .027) and higher rate of out-of-field failure (P = .029) as compared with the wild-type EGFR group. There was no significant difference in the rate of in-field failure or out-of-field failure between the ALK-positive and ALK-negative groups. Conclusions: Although the ALK-positive group showed no characteristic failure pattern, the EGFR-mutant group showed a lower rate of in-field failure and higher rate of out-of-field failure. (C) 2019 The Author(s). Published by Elsevier Inc.