Purpose To assess the survival impact of pre-concurrent chemoradiotherapy (CCRT) staging with positron emission tomography-CT (PET-CT) in patients with unresectable epidermal growth factor receptor (EGFR) mutation-positive adenocarcinoma.

Methods Patients with unresectable stage IIIA–IIIC EGFR mutation-positive adenocarcinoma undergoing definitive CCRT were divided into two groups: those who received PET-CT staging prior to CCRT and those with other staging methods. Survival outcomes were compared after propensity score matching.

Results Analysis of 11 856 patients (5928 in each group) showed that PET-CT staging was associated with improved survival (adjusted HR of all-cause mortality: 0.74, 95% CI 0.71 to 0.79). Other prognostic factors included male sex, age group, clinical stage, adjuvant treatment, smoking status, Charlson Comorbidity Index score and treatment setting.

Conclusion Pre-CCRT staging with PET-CT in patients with unresectable EGFR mutation-positive adenocarcinoma of clinical stage IIIA–IIIC was associated with enhanced survival. Independent prognostic factors were also identified.

Data may be obtained from a third party and are not publicly available. Data analysed during the study were provided by a third party. Requests for data should be directed to the provider indicated in the Acknowledgments section. We used data from the National Health Insurance Research Database and Taiwan Cancer Registry database. The authors confirm that, for approved reasons, some access restrictions apply to the data underlying the findings. The data used in this study cannot be made available in the manuscript, the supplemental files or in a public repository due to the Personal Information Protection Act executed by Taiwan’s government, starting in 2012. Requests for data can be sent as a formal proposal to obtain approval from the ethics review committee of the appropriate governmental department in Taiwan. Specifically, links regarding contact info for which data requests may be sent to are as follows: NHIRD Data Subsets and NHIS Data Access. The data sets supporting the study conclusions are included in the manuscript.