Tobacco smoking: A factor of early onset of colorectal cancer

PURPOSE: Tobacco smoking is associated with a higher risk of developing colorectal cancer. This study was designed to assess the role of smoking in early onset of colorectal pathology. METHODS: This was a prospective cross-sectional study of 997 patients with colorectal cancer. Age of colorectal cancer diagnosis was studied in two groups of patients, i.e., smokers (> 10 pack-years) and nonsmokers. Confounding factors, such as alcohol drinking, obesity, and gender, also were studied using a correlation analysis and multivariate logistic regression analysis. RESULTS: Of the 997 patients, 852 had sufficient data for analysis and were included. Baseline analysis showed that excluded patients had similar demographic characteristics. Smokers (n = 108) reported symptoms related to colorectal cancer at an earlier mean age (64.1 (standard deviation, 11.7) years) than nonsmokers (69.6 (standard deviation, 12.6) years; mean difference, 5.5 (standard deviation, 1.2 years); P < 0.001). Impact of smoking according to the bowel segment involved was significant for slow-transit segments (transverse and sigmoid colon and rectum). Multivariate analysis revealed that tobacco smoking was the only independent risk factor of early onset of colorectal cancers. CONCLUSIONS: Tobacco smoking could be a factor of early onset of colorectal cancers especially for slow-transit bowel segments. If these findings are confirmed in larger studies, screening for colorectal cancer should not involve a simple sigmoidoscopy but also an exploration of transverse colon in smokers.