Abstract
BACKGROUND: Post-diagnosis smoking remains prevalent among head and neck squamous cell carcinoma (HNSCC) patients. Smoking cessation may improve patient outcomes. METHODS: A prospective longitudinal cohort study (2008-2014) included 835 newly diagnosed HNSCC patients and followed up for 7 years. Participants were categorized by smoking behavior (never smokers, former smokers, quitters, continuing smokers, and intermittent smokers). The primary outcomes were overall survival (OS) and recurrence-free survival (RFS). RESULTS: Smoking cessation after diagnosis was associated with significantly improved OS. Quitters had a 61% reduction in mortality risk compared to continuing smokers (HR: 0.39, 95% CI: 0.22, 0.69), with the greatest benefit in oral cavity cancer patients (HR: 0.28, 95% CI: 0.12, 0.65). Intermittent smokers also showed improved survival (HR: 0.50, 95% CI: 0.31, 0.79). RFS did not significantly differ based on smoking behavior. CONCLUSIONS: Smoking cessation post-diagnosis improves OS, particularly in oral cavity cancer patients, highlighting the importance of targeted smoking cessation interventions in HNSCC care.