Matched-Pair Analysis of Survival of Never Smokers and Ever Smokers With Squamous Cell Carcinoma of the Head and Neck

Abstract

Purpose To compare survival rates between patients with squamous cell carcinoma of the head and neck (SCCHN) without a history of smoking (never smokers) and those with a current or previous history of smoking (ever smokers). Patients and Methods Fifty never smokers with newly diagnosed SCCHN were matched to 50 ever smokers according to sex, age, tumor site, overall stage, nodal stage, and treatment. Survival analysis was performed using Kaplan-Meier estimates. Matched-pair survival was compared using the Cox proportional hazards model. Results The never smokers had a greater overall survival (P = .020), disease-specific survival (P = .022), and recurrence-free survival (P = .016). Furthermore, matched-pair analysis demonstrated smoking was associated with a significant increase in risk of overall death (relative risk [RR] = 3.50; 95% CI, 1.14 to 10.77; P = .029), risk of death owing to disease (RR = 3.98; 95% CI, 1.11 to 14.33; P = .034), and risk of disease recurrence (RR = 3.29; 95% CI, 1.18 to 9.14; P = .023). Smoking was associated with three-fold increases in risk for overall death, death owing to disease, and recurrence after adjustment for cancer-associated symptom severity and alcohol use, but the 95% CI for these adjusted risk estimates each included the null. Conclusion Survival differed significantly between never smokers and ever smokers with SCCHN. These results are not substantively explained by differences in cancer-associated symptoms or alcohol use, but the CIs are wide and some imprecision remains. Regardless, possible fundamental differences in SCCHN between ever smokers and never smokers may exist, and further molecular characterization of these tumors is needed to determine whether biologic differences needing targeted therapies exist.