Colorectal cancer originates in the colon or rectum, the terminal end of the digestive tract. The secular trend of colorectal cancer has been increasing in developing countries globally, including Thailand. It is the third most common cancer worldwide. According to the World Health Organisation (WHO), there are about 1.9 million newly diagnosed colorectal cancer cases annually, with over 900,000 deaths in 2020. In Thailand, colorectal cancer is the most common cancer in men, accounting for 20.7%, and the second most common cancer in women, accounting for 12.2% of all cancers diagnosed in 2020.
Colorectal cancer can affect anyone, but certain factors can increase an individual's risk. Advancing age is one of the significant risk factors for colorectal cancer, increasing as people get older, particularly over 50. African Americans carry a higher individual risk of developing colorectal cancer than other ethnic groups. Other risk factors for colorectal cancer include a family history of colorectal cancer or polyps, a history of certain colorectal diseases, particularly inflammatory bowel disease (IBD; Crohn's and ulcerative colitis), and some genetic syndromes. Modifiable factors that can increase the risk of developing colorectal cancer include smoking, alcohol consumption, unhealthy diets such as those high in red and processed meat, and a lack of physical activity.
