1202O - Clinical and biological characteristics of non-small cell lung cancer (NSCLC) harbouring EGFR mutation: Results of the nationwide programme of the French Cooperative Thoracic Intergroup (IFCT)

Abstract

EGFR mutations are associated with variable response to EGFR-TKI depending on the types of exons, mutations or clinical characteristics. To better understand these features we reviewed all cases of EGFR mutated NSCLC collected in the Biomarkers France database (Barlesi et al, Lancet 2016). Among the 17,664 patients, 1837 (10.3%) with an EGFR mutated NSCLC were analyzed for their biological and clinical characteristics. EGFR exon 18, 19, 20 and 21 mutations were found in 102 (5.6%), 931 (50.6%), 102 (5.6%) and 702 (38.2%) patients among which 70 had never been described. Proportion of smokers was higher in exon 18 (20%) and exon 20 (19%) compared to exon 19 (11%) and 21 (11%) (p = 0.002). Personal history of cancer was related in 226 patients (19.2%), irrespective of the exons. T790M mutated patients (n = 42) were excluded for survival analysis. Median follow-up was 36.7 [36.4-37] months. Median overall survivals (OS), first-line progression-free survivals (PFS) and disease control rates (DCR) under first-line EGFR-TKI according to the type of EGFR mutation are summarized in table 1. Median OS was longer for exon 19 deletions compared to L858R mutations (26.5 vs. 21.3 months, p = 0.045). In exon 19, there was no difference in OS based on the length of the deletion. In exon 21, median OS was longer for L858R than for L861Q or other substitutions or wild-type (22.4 vs. 14.1 vs. 14.9 vs. 11.8, p = <0.0001). DCR under first-line EGFR-TKI was 82, 77 and 54.5% for common, rare and complex mutations respectively (p = 0.05). There was no difference in DCR under EGFR-TKI based on the type of mutation in exon 19 (deletions vs. delins vs. substitutions) or 21 (L858R vs. L861Q vs. others).Tabled 1Wild-typeExon 18Exon 19Exon 20Exon 21pOS, months11.8 [10.1-13.3] (n = 1270)14.2 [12.4-NR] (n = 44)27.0 [23.4-29.1] (n = 555)16.0 [8.1-19.1] (n = 50)21.3 [18.5-27.8] (n = 439)<0.001PFS first-line, months7.2 [6.3-7.9] (n = 1243)12.4 [5.8-NR] (n = 44)16.3 [13.9-18.0] (n = 560)6.4 [2.9-9.0] (n = 48)13.7 [11.6-16.1] (n = 442)<0.0001DCR (TKI), %21 (n = 14)78 (n = 9)82 (n = 235)20 (n = 5)81 (n = 201)<0.0001 Open table in a new tab Common and non-common EGFR mutations presented different clinical characteristics. Among common mutations, exon 19 mutated patients had better outcomes.