The clinical prognostic factors in advanced lung adenocarcinoma patients with different EGFR mutation subtype.

Abstract

e20680 Background: The prognostic factors of advanced NSCLC patients with EGFR mutation subtypes remains controversial. This study aimed to investgate the association of clinical prognostic factors with EGFR-TKI efficacy in advanced lung adenocacinoma patients with different EGFR mutation subtypes. Methods: The clinical characteristics, treatment and survival data of advanced lung adenocarcinoma patients with EGFR sensitive mutations who were treated with Icotinib (Betta Pharmaceuticals, China) from January 2011 to December 2017 in our medical center were reviewed. The prognositic factors of patients between with EGFR exon 19 deletion (19-Del) and exon 21 Leu858Arg mutation (L858R) were retrospectively analyzed by using the Kaplan-Meier method, the chi-square test, and multivariate Cox hazards model. Results: A total of 187 patients were enrolled in the study, including 104 patients with EGFR19-Del and 83 patients with EGFR21-L858R. The results showed that no significant difference in mPFS between the two groups (19-Del vs. L858R: 15.0 months, 95% CI 17.2-32.8months vs. 13.0 months 95% CI 11.7-14.3 months, p = 0.347), while the mOS of patients with 19-Del (35months, 95% CI 28.6-41.4 months) was significantly better than that of patients with EGFR21-L858R (25 months, 95%CI 17.2-32.8 months, p = 0.020). For PFS, liver metastasis was an independent prognostic factor in EGFR19-DEL patients (HR 5.009, 95%CI 1.296-19.354, p = 0.019), while gender (HR 5.881, 95%CI 2.105-16.431, p = 0.001), smoking status (HR 6.972, 95%CI 2.851-17.049, p = 0.001), lymph node metastasis (HR 2.676, 95%CI 1.002-7.148, p = 0.050) were independent prognostic factors in patients with L858R. As for OS, age (HR 1.080, 95%CI 1.017-1.147, p = 0.012), brain metastases (HR 23.166, 95%CI 3.946-136.009, p = 0.001), liver metastases (HR 14.088, 95%CI 1.782-111.385, p = 0.012), renal or adrenal metastasis (HR 10.558, 95%CI 1.480-75.326, p = 0.019), TKI initial efficacy (HR 6.638, 95%CI 2.743-16.067, p = 0.001) were independent prognostic factors in patients with 19-del, however, the initial efficacy of TKI (HR 6.089, 95% CI 2.669-13.893, p = 0.001) was an independent prognostic factor in patients with L858R. Conclusions: The mOS of patients with EGFR 19-Del treated with Icotinib was significantly better than that of patients with L858R, while the mPFS of both were similar. Moreover, there are significant differences in prognostic factors of advanced lung adenocarcinoma patients between with 19-Del and L858R subtypes, which may be helpful for the clinical treatment strategy of EGFR-TKI.