Objective: This study evaluated the joint effects of tobacco smoking and alcohol consumption on the risk of second primary tumors (SPT) in patients with early-stage head and neck squamous cell carcinoma (HNSCC).
Methods: Data are presented for 1181 patients enrolled in a placebo-controlled chemoprevention trial of 13-cis-retinoic acid. Nearly 17% of patients presented with a SPT. The log rank test and Cox proportional hazards model were used to examine risk factors for SPT development.
Results: After adjusting for the time from the index diagnosis to randomization, age at diagnosis, stage, and site of the primary cancer, the factors that emerged as simultaneous predictors of SPT development were continued smoking and alcohol intake after the index diagnosis. Increased SPT risk was associated with older age (RR = 2.1; 95% CI 1.5-2.8); stage II diagnosis (RR = 1.5; 95% CI 1.1-2.1); index diagnosis of pharyngeal cancer (RR = 1.6; 95% CI 1.1-2.5); current smoking at registration (RR = 2.1; 95% CI 1.3-3.6) and continued alcohol consumption post-diagnosis (RR = 1.3; 95% CI 1.0-1.7).
Conclusion: Important associations exist between SPT development and continued smoking and alcohol consumption after treatment for HNSCC.