This study aimed to determine the progression-free survival (PFS), overall survival (OS), objective response rate (ORR) and disease control rate (DCR) in patients with locally advanced or metastatic lung adenocarcinoma treated with first-line epidermal growth factor receptor -tyrosine kinase inhibitor (EGFR-TKI) versus chemotherapy.
A retrospective cohort observational study of patients with locally advanced (stage IIIB) or metastatic (stage IV) lung adenocarcinoma treated with first-line EGFR-TKI or chemotherapy at University Malaya Medical Centre from 1st August 2010 to 31th July 2014.
Of 117 patients with EGFR mutation-positive tumours, the median PFS (6.93 months) for those treated with first-line EGFR-TKI (n = 98) was significantly longer than the median PFS (2.23 months) for those treated with first-line chemotherapy (n = 19) (HR, 0.50; 95% CI, 0.29 - 0.84; p = 0.010). The median OS was similar [10.40 months for first-line EGFR-TKI versus 9.63 months for first-line chemotherapy (HR, 0.92; 95% CI, 0.49–1.73; p = 0.797)]. The ORR for first-line EGFR-TKI and first-line chemotherapy was 42.9% and 10.5%, respectively (OR, 6.38; 95% CI, 1.40–39.11; p = 0.017) while the DCR was 79.6% and 36.8%%, respectively (OR, 6.69; 95% CI, 2.33–19.19; p < 0.001). Of 101 patients with EGFR mutation-negative tumours, the median PFS (2.93 months) and OS (10.43 months) for those treated with first-line chemotherapy (n = 85) was better than the median PFS (1.03 months) and OS (1.07 months) for those treated with first-line EGFR-TKI (n = 16) (HR for disease progression, 0.44; 95% CI, 0.25 - 0.77; p = 0.004; HR for death, 0.24; 95% CI, 0.12 - 0.77; p < 0.001). The ORR and DCR for first-line chemotherapy was 16.5% and 51.8%, respectively. No patient responded or had disease stabilisation with first-line EGFR-TKI.
This study showed the superiority of first-line EGFR-TKI over chemotherapy in patients with EGFR mutation-positive locally advanced or metastatic lung adenocarcinoma in terms of PFS, ORR and DCR. On the other hand, patients with locally advanced or metastatic EGFR wild-type lung adenocarcinoma do not respond to first-line EGFR-TKI. They had poorer PFS and OS when treated with first-line EGFR-TKI compared to first-line chemotherapy.
Clinical trial identification
All authors have declared no conflicts of interest.