Kim HJ, et al. - In this nationwide, population-based, longitudinal retrospective analysis, researchers investigated the relative risk of nasal cavity and paranasal sinus (NCPS) and nasopharyngeal cancers among patients with nasal polyps (n = 453,892) and matched comparators (n = 4,583,938). They used the 2005-2017 National Health Insurance claims and National Health Screening program databases. Participants were observed over a mean duration of 6.2 years (range, 2-13 years). Despite a very low absolute cancer incidence, a significantly greater relative risk of NCPS or nasopharyngeal cancers was observed in older patients with nasal polyps. The incidence rate ratios of patients with nasal polyps vs with comparators was 7.00 for NCPS cancer and 1.78 for nasopharyngeal cancer; only in older subjects (age ≥50 years) were increased risks of these cancers apparent. In younger patients with comorbid asthma or allergic rhinitis (<50 years) the associations of nasal polyps with these cancers were weaker.