Rethinking smoking assessment in head and neck squamous cell carcinoma: are we missing something?

Tobacco exposure is a major determinant of risk and clinical outcomes in head and neck squamous cell carcinoma (HNSCC). Although pack-years have long represented the standard metric for quantifying smoking exposure, increasing evidence suggests that this approach incompletely captures the biological and clinical heterogeneity of tobacco-related risk.

Recent epidemiological and clinical studies demonstrate that smoking duration rather than its intensity or cumulative pack-years measures is a stronger predictor of HNSCC risk and overall survival, particularly among long-term smokers. Regarding cumulative metrics, metrics like log cigarette-years have shown a better prognostic role when compared with pack-years. Beyond cumulative or duration-based models, smoking cessation and the use of alternative tobacco products substantially influence HNSCC risk and clinical outcomes. While smoking cessation is associated with a progressive reduction in risk and improved survival, active smoking at diagnosis is consistently associated with inferior treatment response. In parallel, non-cigarette tobacco products-including cigars, pipes, and smokeless tobacco-have been shown to independently increase HNSCC risk, are rarely incorporated into exposure models. The growing use of alternative nicotine-containing products, often in combination with cigarette smoking, further complicates risk assessment, as their long-term carcinogenic and immunomodulatory effects remain incompletely characterized.

Pack-years-based models alone are insufficient for accurate risk stratification in HNSCC and realize integrated models including smoking duration assessment may improve prognostic and predictive accuracy, supporting more personalized treatment strategies.