Smoking and Colorectal Cancer Risk, Overall and by Molecular Subtypes: A Meta-Analysis

Cigarette smoking increases the risk of CRC in a dose-dependent manner with intensity and duration, and quitting smoking reduces CRC risk. Smoking greatly increases the risk of CRC that develops through the microsatellite instability pathway, characterized by microsatellite instability-high, CpG island methylator phenotype positive, and BRAF mutation.