EGFR mutation prevalence in Asia-Pacific and Russian patients with advanced NSCLC of adenocarcinoma and non-adenocarcinoma histology: The IGNITE study

Abstract

Objectives: Limited understanding exists of epidermal growth factor receptor (EGFR) mutation frequency in less common subgroups of advanced non-small-cell lung cancer (aNSCLC) (e.g. squamous cell carcinoma [SCC]), and to what extent local practices exclude patients from EGFR testing based on their clinical characteristics.

Materials and methods: IGNITE (non-comparative/-interventional; NCT01788163) was conducted in 90 centres (Asia-Pacific/Russia). Eligible patients: local/metastatic aNSCLC; chemotherapy-naïve, newly-diagnosed/recurrent disease after resection; ineligible for curative treatment. Patients provided a tissue/cytology (all) and a blood plasma (China/Russia/South Korea/Taiwan) sample. Primary endpoint: EGFR mutation frequency in aNSCLC patients (adenocarcinoma [ADC]/non-ADC), as per local practices.

Results: 3382 patients were enrolled. EGFR mutation frequencies for evaluable tissue/cytology samples in Asia-Pacific and Russian patients: 49.3% (862/1749) and 18.0% (90/500) for ADC tumours; 14.1% (74/525) and 3.7% (15/402) for non-ADC; 9.9% (40/403) and 3.7% (13/349) for SCC. Of Russian patients with SCC tumours harbouring common, activating EGFR mutations, 6/9 were never-/former-smokers. Mutation status concordance between 2581 matched tissue/cytology and plasma samples: 80.5% (sensitivity 46.9%, specificity 95.6%).

Conclusion: EGFR mutation testing should be considered in all Asian aNSCLC patients. Also, as activating EGFR mutations were observed in a small number of Caucasian squamous NSCLC patients, testing here may be appropriate, particularly in those with no/remote smoking history. Circulating free tumour-derived DNA is feasible for mutation analysis employing well-validated and sensitive methods, when tumour samples are unavailable.

Keywords: Adenocarcinoma; Circulating free tumour-derived DNA; Diagnostic; Epidermal growth factor receptor; Non-small-cell lung cancer.