Less than 5% of the cancers are considered genetic cancers. These are conditions due to abnormalities in the genetic constitution of the patient.
In Singapore, the lifetime risk of colorectal cancer is about 2%. Most colon and rectal cancer occurs in patients over the age of 50 years, though this does not mean that people below that age will never get colorectal cancer.
The risks increases when one has close family members with colorectal cancer.
When there is a first degree relative (parents, siblings or children) with colorectal cancer, the risks increase 3 times to about 6%. If this relative is below the age of 50 at the time of diagnosis, the risk goes up to about 10%. If there are 2 first degree relative (for example, father and brother) with colorectal cancer, the risk is 17%. With 3 first degree relative, the risk is almost 50%.
If you have a history of polyps (adenoma type) or colorectal cancer, there is an increased risk of getting a cancer / 2nd cancer. The greater the number of polyps and the earlier the age of the first cancer, the higher the risk
Inflammatory bowel disease is a type of chronic inflammation of the intestines. This is more common in the Caucasian population than in Asia. The risk of colorectal cancer is increased with people with this condition and they require long term specialist care for treatment, surveillance and cancer prevention. In certain cases, they are recommended to have colorectal surgery to remove the entire colon and rectum to avoid developing cancer.