Alcohol, smoking and the risk of premalignant and malignant colorectal neoplasms.

Colorectal cancer (CRC) is the third most common cancer worldwide and has a complex aetiology consisting of environmental and genetic factors. In this review, we evaluate the roles of alcohol and tobacco smoking in colorectal neoplasia. Alcohol intake and tobacco smoking are associated with modest, but significantly, increased risks of CRC, adenomatous and serrated polyps. There is consistent evidence of dose-response relationships for both alcohol and smoking, and risk of these neoplasms. Alcohol and smoking appear to be more strongly associated with colorectal polyp than CRC development, suggesting roles in the initiation of neoplastic growths. These lifestyle factors also seem more strongly related to adenomas and sessile serrated lesions than hyperplastic polyps, but further confirmation is required. The gastroenterology community has an important, yet currently underexploited, role to play addressing the modifiable factors associated with CRC and polyps. These behaviours include, but are not limited to, alcohol and smoking.