Predictors of lung cancer: noteworthy cell type differences.

OBJECTIVE To study risk factors for cell types of lung cancer. METHODS Cohort study of 126,293 persons with 1852 subjects with incident cancer. We performed Cox proportional hazards models (8 covariates) to estimate risk of the 4 most numerous specific cell types: adenocarcinoma, squamous cell carcinoma, small cell carcinoma, and bronchioloalveolar carcinoma. RESULTS Smoking 1 or more cigarette packs per day was a powerful predictor (p < 0.0001) of all cell types, with hazard ratios ranging from 5.8 for bronchioloalveolar to 62.7 for squamous cell carcinoma. Other hazard ratio ranges included male/female from 0.6 (bronchioloalveolar, p < 0.05) to 2.0 (squamous, p < 0.001); black/white from 0.8 (small cell, p < 0.05) to 1.7 (squamous, p < 0.001); Asian/white from 0.8 (small cell) to 1.9 (bronchioloalveolar); and alcohol intake of 3 or more drinks per day from 1.0 (squamous) to 1.5 (adenocarcinoma, p < 0.01). College graduation and increasing body mass index were inversely related to risk of several cell types. Noteworthy sex-specific associations included increased risk of Asian vs white women for adenocarcinoma, squamous cell carcinoma and bronchioloalveolar carcinoma and substantially increased risk of adenocarcinoma in women with alcohol intake of 3 or more drinks per day. CONCLUSIONS These risk factor disparities for lung cancer cell types presumably reflect biologic differences. Future investigation may contribute to increased understanding of tumorigenesis and optimal treatment.