INCREASED RISK

An individual at increased risk has a personal or family history of colorectal cancer or adenomatous polyps but does not have one of the high-risk familial syndromes. The individual who is at increased risk doesn’t need, and is generally not given, options. This individual should be encouraged to have a colonoscopy. This situation is not rare. A significant percentage of the general population (18 to 20 percent) is at increased risk. Increased risk is common because age is a defining risk factor for Colorectal Cancer and the prevalence of adenomatous polyps rises as people get older. It is 20 to 25 percent by age 50, and 50 percent by age 75 to 80.  While only a limited percentage of adenomatous polyps turn into cancers, these polyps are the precursors of colorectal cancers.

Both personal history and family history are deciding factors in the determination of risk status. Increased risk may be caused by a personal history of adenomatous polyps or colorectal cancer, or a family history of adenomatous polyps or colorectal cancer. A family history of adenomas or Colorectal Cancer under age 50 should lead to suspicion of a high-risk situation and further evaluation. The individual with a personal history of Colorectal Cancer or adenomatous polyps requires regular surveillance, not screening. Surveillance recommendations for such individuals were recently updated.

The risk factor of a family history of adenoma is frequently overlooked. More attention needs to be given to this risk factor. A family history of an adenomatous polyp in a first-degree relative under age 60 should lead to screening starting at age 40 or earlier.

A family history of a polyp of unknown type should be managed as if it were an adenoma. Another factor of personal history that can raise the risk level is a personal history of chronic inflammatory bowel disease (ulcerative colitis or Crohn’s disease). Risk is regarded as increased when there is a personal history of these diseases for more than eight years.

Individuals at increased risk should begin screening earlier (age 40 or younger), be screened more frequently, and use the most sensitive screening modality available. At this time, colonoscopy is both the most sensitive and the most specific screening modality available. It is worth remembering that only the absence of risk factors confers a state of average risk. New evidence regarding the most common location for adenomatous polyps has raised questions about an imperative for colonoscopy screening in populations that have a tendency to exhibit polyps in the proximal colon.