Use of nonaspirin nonsteroidal anti-inflammatory drugs and risk of head and neck cancer: A nationwide case-control study.

Head and neck cancer (HNC) is the sixth most frequent malignancy with high mortality and substantial morbidity and hence there is a need for identification of preventive factors. Preclinical and observational studies have reported antineoplastic effects of nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs), but studies of nonaspirin NSAID use and risk of HNC are sparse and with inconsistent results. We therefore conducted a register-based case-control study nested in the entire Danish population. Cases (n = 12,389) comprised all Danish residents aged 30-84 years with a histologically verified primary HNC diagnosis during 2000-2015. Based on the literature, cases were categorized into four groups of anticipated association with human papillomavirus (HPV): strong, potential, no/weak and uncertain. Age- and sex-matched population controls (n = 185,835) were selected by risk-set-sampling. We obtained information on filled prescriptions of nonaspirin NSAIDs, other drug use, comorbid conditions and socioeconomic parameters from nationwide Danish registries. Ever-use (≥2 prescriptions) of nonaspirin NSAIDs was not associated with the overall risk of HNC after adjustment for potential confounders (odds ratio [OR]: 0.99, 95% confidence interval [CI]: 0.95-1.03). However, long-term consistent use (≥5 years) was associated with a 25% reduction in HNC risk (OR: 0.75, 95% CI: 0.62-0.90). Stratified analyses by anticipated HPV-association showed no material differences in estimates. In conclusion, ever-use of nonaspirin NSAIDs was not associated with the risk of HNC with no apparent influence on the estimates by the anticipated HPV-association. However, long-term consistent use may be associated with a reduced risk of HNC and merits further investigation.