A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.
A person with an average risk of colorectal cancer has about a 5% chance of developing colorectal cancer overall. Generally, most colorectal cancers (about 95%) are considered sporadic, meaning the genetic changes develop by chance after a person is born, so there is no risk of passing these genetic changes on to one’s children. Inherited colorectal cancers are less common (about 5%) and occur when gene mutations, or changes, are passed within a family from one generation to the next (see below). Often, the cause of colorectal cancer is not known. However, the following factors may raise a person’s risk of developing colorectal cancer: