Association of smoking status, duration and amount with the risk of head and neck cancer subtypes: a national population-based study.

Smoking is positively associated with multiple cancer types including head and neck cancer (HNC). We sought to confirm the effect of smoking in HNC and subtypes through big data analysis. All data used in this study originated from the Korean National Health Insurance Service database. We analyzed subjects who had undergone health check-ups in 2009 with follow-up until 2018 (n=10,585,852). We collected data on smoking and other variables that could affect the risk of HNC. The overall incidence of HNC was highest in current smokers (HR: 1.822, 95% CI: 1.729-1.920), followed by ex-smokers (HR: 1.242, 95% CI: 1.172-1.317). Laryngeal cancer, hypopharynx cancer, oral cancer, oropharyngeal cancer, and salivary gland cancer showed increasing incidence rates from ex-smokers to current smokers. Smoking duration and amount showed a dose-dependent relationship with the occurrence of HNC. However, the incidence of HNC did not increase significantly when smoking duration was less than 10 years, or when the smoking amount was less than 10 pack-years in ex-smokers. Smoking is associated with the risk of HNC. Smoking cessation before 10 years or 10 pack-years can prevent the development of HNC.