[Comparison of clinical outcomes of patients with non-small cell lung cancer harboring different types of epidermal growth factor receptor sensitive mutations after first-line EGFR-TKI treatment].

OBJECTIVE: To analyze whether there are differences in the efficacy and clinical outcomes to first-line tyrosine kinase inhibitors (TKI) therapy in Chinese patients with metastatic non-small-cell lung cancer (NSCLC) harboring different subtypes of epidermal growth factor receptor (EGFR) mutations.

METHODS: A retrospective analysis was made on the clinical data of stage ⅢB or Ⅳ NSCLC patients who were diagnosed by histology and received EGFR mutation test, in order to confirm if there is any difference between the therapeutic effects of TKIs as first-line therapy and the prognosis.

RESULTS: A total of 165 patients harboring EGFR exon 19 deletion (19del, n=71), exon 21 L858R mutation (L858R, n=80) or uncommon sensitive mutation (n=14) were treated with EGFR-TKIs for first-line treatment. The comparison among different groups of common types of sensitive mutations revealed that the objective response rate (ORR) of group 19del and group L858R were 57.8% and 45.0%, respectively (P=0.113). The disease control rate (DCR) was 93.0% and 93.8%, respectively (P=0.158). However, the ORR and DCR of uncommon sensitive mutation were 35.7% and 78.6%, which were significantly lower than that of the group 19del (P=0.035) and group L858R (P=0.020). The median progression-free survival (PFS) of group 19del, group L858R and uncommon sensitive mutation were 14.0 months, 7.8 months and 5.1 months, respectively (P=0.001). The median PFS of the group 19del was significantly longer than that of the group L858R (P=0.009). The median overall survival (OS) of these three groups had significant difference (22.8, 15.2 and 10.0 months) (P=0.048). But those of group 19del and group L858R were similar (P=0.152). The multivariate analysis indicated that ECOG-PS (P=0.030), cigarette smoking (P=0.013) and EGFR mutation types (P=0.034) are independent prognostic factors of OS.

CONCLUSIONS: For Chinese NSCLC patients with different types of sensitive mutation, there are differences between their efficacy and prognosis of EGFR-TKIs as first-line treatment. The PFS of group 19del is obviously longer than that of other types of sensitive mutations, but have no significant differences in OS. The PFS and OS of patients with common types of sensitive mutation are better than those with uncommon sensitive mutation.