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.