Some people are more likely to develop colorectal cancer than others. Studies have found that certain factors increase a person’s risk. The following are risk factors for this disease:

• Polyps – Most (perhaps all) colorectal cancers develop in polyps. Polyps are benign, but they may become cancerous over time. Removing polyps is an important way to prevent colorectal cancer.
• Age – Colorectal cancers occur most often in people who are over the age of 50, and the risk increases as people get older.
• Family history – Close relatives of a person who has had colorectal cancer have a higher than average risk of developing the disease. The risk for colon cancer is even higher among members of a family in which many relatives have had it. (In such cases, the disease is called familial colon cancer.)
• Familial polyposis – This is an inherited condition in which hundreds of polyps develop in the colon and rectum. Over time, these polyps can become cancerous. Unless the condition is treated, a person who has familial polyposis is almost sure to develop colorectal cancer.
• Diet – The risk of developing colon cancer seems to be higher in people whose diet is high in fat, low in fruits and vegetables, and low in high-fiber foods such as whole-grain breads and cereals.
• Ulcerative colitis – This disease causes inflammation of the lining of the colon. The risk of colon cancer is much greater than average for people who have this disease, and the risk increases with the length of time they have had it.