Cancer that begins in the large intestine or colon is called colon or colorectal cancer. When the colon cells or rectum cells undergoes a mutation, it hinders their ability to manage growth and division, which causes them to form a tumor. It starts as polyps that are noncancerous clumps of cells; however, over time, some of them can turn into colon cancer. Though the exact causes are unknown, physicians have listed the following important risk factors for colon cancer:

1. Genetics
Various genetic factors are associated with the development of colon cancer:

• Familial Adenomatous Polyposis (FAP)
  Most colorectal cancers result from adenomatous polyps which are made of a higher number of both normal and abnormal appearing cells. These polyps appear on the glands of the inner wall of the colon. These cells develop into adenocarcinomas over time. People with certain genetic abnormalities are likely to develop familial adenomatous polyposis syndrome. They carry a higher risk of colon cancer and generally run in the family before it can cause cancer for around 40 years.
• Hereditary Non-Polyposis Colorectal Cancer (HNPCC)
  It is also associated with genetic abnormality and colon cancer in this syndrome develops without any polyps. Sometimes, this can cause tumors to occur in different parts of the body.
• Other inherited syndromes
  The other inherited syndromes that act as an important risk factor for colon cancer are Crohn’s disease, ovarian cancer, breast cancer, or uterine cancer either at present or in the past.

2. Lifestyle
An unhealthy lifestyle can also be the cause for the occurrence of colon cancer.

• Diet
  The role of an unhealthy diet being the cause of colon cancer is up for debate, though it is believed that diets rich in red and processed meats such as lamb and beef increase the chances of colon cancer. Various cooking methods such as grilling and broiling at high temperatures creates chemicals that act as high-risk factors for colon cancer. On the other hand, diets that contain high-fiber grains and fruits and vegetables can reduce the risks of colon cancer.
• Smoking and alcohol consumption
  Smoking and consuming high amounts of alcohol are also associated as causes of colon cancer.
• Inactive lifestyle
  People who spent most of their time sitting or lying down with almost little to no physical activity bear the risk of developing this type of cancer.

3. General causes of colon cancer
Apart from genetic and lifestyle factors, the following reasons can also act as important risk factors for colon cancer:

• Age
  Colon cancer can make an appearance at any age; however, the risk of developing the disease increases after the age of 45.
• Inflammatory bowel diseases (IBD)
  A person suffering from inflammatory bowel disease along with ulcerative colitis and Crohn’s disease is likely to suffer from this form of cancer. The risk increases the level of IBD and how much the colon is affected.
• Obesity
  Obese people also are under the risk of developing colon cancer.