Efficacy and prognosis comparison of first-line treatment with EGFR-TKI versus chemotherapy for non-small cell lung cancer patients harboring EGFR rare mutation / 肿瘤研究与临床

ABSTRACT

Objective:To investigate the therapeutic effect difference between first-line treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) and chemotherapy in non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) rare mutation.Methods:A retrospective case-control study was performed. Data of NSCLC patients with rare EGFR mutation who were treated in Shanxi Province Cancer Hospital from January 2013 to October 2019 were retrospectively analyzed. EGFR mutations in living tissues or blood were detected by using amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) before first-line treatment. According to first-line treatment methods,they were divided into EGFR-TKI treatment group and chemotherapy group. Objective remission rate (ORR) and disease control rate (DCR) of both groups were compared. Kaplan-Meier method was used to draw progression-free survival (PFS) and the overall survival (OS) curves. Log-rank test was used for comparison among groups. Single-factor and multi-factor Cox proportional risk models were used to analyze the influencing factors of PFS and OS.Results:A total of 169 patients with EGFR rare mutations were included, and the age [ M (IQR)] was 63 years (12 years); there were 96 cases (56.8%) < 65 years and 73 cases (43.2%) ≥65 years; 70 (41.4%)males and 99 (58.6%) females; 55 cases (32.5%) had EGFR G719X mutation,45 cases (26.6%) had L861Q mutation, 17 cases (10.1%) had S768I mutation, and 52 cases (30.8%) had complex mutation; 55 cases (32.5%) received the first-line chemotherapy and 114 cases (67.5%) received the first-line EGFR-TKI treatment. In the chemotherapy group, ORR was 36.4% (20/55) and DCR was 85.5% (47/55); in EGFR-TKI treatment group, ORR was 72.8% (83/114) and DCR was 90.4% (103/114). The ORR of EGFR-TKI treatment group was higher than that of chemotherapy group ( χ2 = 20.70, P = 0.001), and there was no statistically significant difference in DCR between two groups ( χ2 = 1.76, P = 0.184). Subgroup analysis showed that ORR in EGFR-TKI treatment group with G719X, L861Q and complex mutations was higher than that of the corresponding mutations in chemotherapy group, and the differences were statistically significant (all P < 0.05), while there were no significant differences in DCR among subgroups (all P > 0.05). The median PFS time was 9.7 months (95% CI: 6.0-13.4 months) and 3.8 months (95% CI: 3.1-7.1 months), respectively in EGFR-TKI treatment group and chemotherapy group, and there was a statistically significant difference in PFS between the two groups ( P < 0.001). The median OS time was 25.6 months (95% CI: 18.0-37.9 months) and 31.7 months (95% CI: 18.0-42.8 months), respectively in EGFR-TKI treatment group and chemotherapy group, and there was no statistically significant difference in OS between the two groups ( P = 0.231). Multivariate Cox regression analysis showed that brain metastasis [with vs. without: HR = 2.306, 95% CI: 1.452-3.661, P < 0.001] and the first-line treatment methods (EGFR-TKI vs. chemotherapy: HR = 0.457, 95% CI:0.317-0.658, P < 0.001) were independent influencing factors for PFS of NSCLC patients with EGFR rare mutation; brain metastasis (with vs. without: HR = 2.087, 95% CI: 1.102-3.953, P = 0.024; unknown vs. without: HR = 2.118,95% CI: 1.274-3.520, P = 0.004) were independent influencing factors for OS of NSCLC patients with EGFR rare mutation. Conclusions:Compared with the first-line chemotherapy, EGFR-TKI first-line treatment could improve objective remission and PFS of NSCLC patients with EGFR rare mutation, while no OS benefit is observed.