Epithelial growth factor receptor (EGFR) mutation status and the treatment of non-small cell lung cancer (NSCLC): A population based quality assurance analysis

We wanted to analyse the prevalence of EGFR-mutation, and how EGFR-mutation analysis has influenced the treatment during the first four years of use. In the Danish Lung Cancer Registry we have identified all 929 patients (56% female) from Funen (484,700 inhabitants) with first occurrence of adenocarcinoma or NSCLC not otherwise specified - diagnosed from July 2010 to June 2014. Chart review was updated in February 2015. The median age was 68 years (range 31 – 96 years), 6.4% were never-smokers and 37.5% ex-smokers. EGFR-mutation status has been determined for 683 patients (73.6%), but has not been possible from the available samples in 89 cases. For 156 patients the analysis has not been requested. The prevalence of EGFR-mutation has been 10.4% in women, 5.4% in men, and 39.2% in never-smokers (no gender difference). The EGFR mutations were proven in cytology samples in 75% of the 56 positive cases. In the first two years of the study period, EGFR-mutation analysis had not been requested or had not been possible for 34.3% of the patients at the initiation of primary therapy with palliative intent. This fraction was reduced to 10.9% in the last two years (p < 0.001, Fisher's exact test). Despite this improvement, the median time from start of diagnostics to start of therapy did not increase (29 days vs. 28 days). Of the 56 patients with an EGFR-mutation 37 have until now been treated with a tyrosine kinase inhibitor (TKI). Eleven patients had radical therapy without the later use of a TKI, one had conventional chemotherapy due to an exon 20 mutation, and seven patients have died without having systemic therapy.