The impact of smoking status on the progression-free survival of non-small cell lung cancer patients receiving molecularly target therapy or immunotherapy versus chemotherapy: A meta-analysis

What is known and Objective Smoking has a notable influence on the efficacy of medications for lung cancer. Previous studies illustrated the correlation between smoking and the efficacy of first-line Epidermal Growth Factor Receptors-Tyrosine Kinase Inhibitors (EGFR-TKIs). The benefit of smokers in immunotherapy was still controversial. Here, we investigated the impact of smoking on clinical outcomes of molecularly targeted therapies or immunotherapy in Non-Small Cell Lung Cancer (NSCLC). Methods We performed meta-analysis including trials comparing EGFR-TKIs, Anaplastic Lymphoma Kinase (ALK) inhibitors or Immune Checkpoint Inhibitors (ICIs) against chemotherapy in NSCLC. The Progression-Free Survival (PFS)-Hazard Ratios (HRs) of two groups served as the index and we used random effects to pool outcomes. Results and discussion Twenty randomized trials were selected. Compared with chemotherapy, treatment with EGFR-TKIs had similar benefit in never-smokers (PFS: HR = 0.46, 95% CI 0.30 to 0.69) and smokers (PFS: HR = 0.68, 95% CI 0.50 to 0.91; p = 0.135) while non-smokers (PFS: HR = 0.32, 95% CI 0.23 to 0.44) had better benefit from first-line EGFR-TKIs than smokers (PFS: HR = 0.54, 95% CI 0.41 to 0.71; p = 0.02). Treatment with ALK inhibitors had similar benefits in never-smokers (PFS: HR = 0.43, 95% CI 0.35 to 0.53) and smokers (PFS: HR = 0.56, 95% CI 0.44 to 0.71; p = 0.406). The benefit of ICIs in smokers (PFS: HR = 0.79, 95% CI 0.64 to 0.98) was significantly greater than never-smokers (PFS: HR = 1.81, 95% CI 1.27 to 2.57; p = 0.004). What is new and Conclusion Smoking status is an important clinical predictor of therapy in NSCLC. Never-smokers and smokers have similar benefit with EGFR-TKIs therapy compared with chemotherapy, while never-smokers have greater benefit after first-line EGFR-TKIs therapy. There was similar benefit in never-smokers and smokers when using ALK inhibitors over chemotherapy. Additionally, ICIs treatment over chemotherapy leads to more favourable PFS in smokers both in first-line and second-line settings.