Inhaled corticosteroids and risk of lung cancer among chronic obstructive pulmonary disease patients: a comprehensive analysis of nine prospective cohorts

Background: It remains uncertain whether there is a protective effect of inhaled corticosteroids (ICs) against lung cancer in chronic obstructive pulmonary disease (COPD) patients. Methods: Databases including PubMed, Web of Science, EMBASE, and Medline were comprehensively searched. Random-effects model meta-analysis was conducted to calculate the hazard ratios (HRs) for lung cancer incidence among ICs users versus non-ICs users in patients with COPD. Stratified analysis was performed based on region and age of each study. This review was registered on PROSPERO (registration number CRD42020159082). Results: Based on data from 181,859 COPD patients with a total follow-up duration of 1,109,339.9 person-years, we identified that the use of ICs in COPD patients was associated with a decreased risk of lung cancer [HR: 0.73, 95% confidence interval (CI): 0.62- 0.86; P<0.001]. The region-specific HRs for lung cancer incidence were 0.62 (95% CI: 0.62-0.86; P=0.004), 0.77 (95% CI: 0.60-0.97; P=0.028) and 0.81 (95% CI: 0.61-1.08; P=0.155) among European, Asian and North American COPD patients, respectively. Additionally, we found the consistent outcome among age groups (=70 years old: HR: 0.73, 95% CI: 0.65-0.99, P=0.043; <70 years old: HR: 0.74, 95% CI: 0.56-0.99, P=0.040). Conclusions: This study demonstrates that ICs have a protective effect against lung cancer in COPD patients. It could provide guidance for clinicians in the prevention of lung cancer among patients with COPD.