Factors associated with improvement in symptoms and quality of life for first-line EGFR-tyrosine kinase inhibitor treatment in patients with EGFR-mutated non-small-cell lung cancer - A multicenter prospective SMILE study

Introduction: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are a standard first-line treatment for advanced EGFR-mutated NSCLC patients. Factors associated with symptoms and quality of life (QOL) improvements have not been investigated. Methods: We conducted a multicenter, prospective study to evaluate improvements in QOL and symptoms in NSCLC patients treated with first-line EGFR-TKIs. QOL was assessed using the instrument of Functional Assessment of Cancer Therapy-Lung questionnaire (FACT-L) and Treatment Outcome Index (TOI). Assessment of symptoms was evaluated using the Lung cancer subscale (LCS). Results: Eligible subjects included 280 patients for endpoint analyses. The mean FACT-L score increased by 4.0 ± 15.56 at Week 2 (p<0.001), 5.1 ± 18.48 at Week 4 (p<0.001), and 4.2 ± 20.27 at Week 12 (p=0.001). Similarly, a 2.3 ± 11.65 (p<0.001), 3.2 ± 13.59 (p<0.001), and 2.4 ± 14.34 (p=0.009) increase in mean TOI score were observed at Weeks 2, 4 and 12, respectively. For LCS, it was slightly increased by 1.7 ± 4.61, 2.0 ± 5.50, and 2.0 ± 5.36 at Weeks 2, 4, and 12 (all p<0.001), respectively. Subgroup analyses showed patients who were ex-smokers or with at least 3 metastatic sites were associated with symptoms improvement. Patients who were ex-smokers, with at least 3 metastatic sites, a PS of 1, or treated with gefitinib were associated with QOL improvement. Conclusions: In EGFR -mutated NSCLC patients who were treated with first-line EGFR-TKIs, these ex-smokers or with 3 or more metastatic sites were associated with improvements in symptoms and QOL.