Family History


One of the risk factors for colon cancer is having a family history of the disease. Most colon cancers occur independently, but an estimated 5 to 10 percent of colon cancers are a direct result of heredity. Therefore, a person who has a family history of colon cancer and eventually develops the disease is more likely to have inherited the cancer gene than a person with no family history of colorectal cancer.


Know Your Family’s History

Knowing your family’s health history is important because certain risk factors such as family history make you a candidate for early screening. Although individuals at average risk for colon cancer should schedule their first colonoscopy at age 45, individuals who are at higher risk need to have a baseline screening earlier. If you have a family history of colon cancer, your doctor can tell you when to have your first colonoscopy.

The most common inherited colorectal syndrome is hereditary nonpolyposis colorectal cancer (commonly known as Lynch syndrome). It affects both genders and can develop at a very young age. The children of men and women who carry the genetic code for HNPCC have a 50 percent chance of inheriting the disease-causing gene.

Lynch Syndrome

The more common type of inherited colon cancer is called hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome. Lynch syndrome accounts for roughly 3 to 5 percent of all colon cancer diagnoses and usually affects family members in two or more generations. Families with a history of Lynch syndrome usually have more family members develop colon cancer than typically expected. While the average age for a new diagnosis of colorectal cancer in the general population is 72, the average age of new diagnosis for someone with Lynch syndrome is only 45 years of age.

The classic diagnostic criteria for Lynch syndrome are:

  • Three or more relatives with a Lynch syndrome-related cancer
  • At least two generations with cancer
  • Family history of young-onset cancer

Screening options for Lynch syndrome include

  • A colonoscopy every 1 to 2 years, beginning at the age of 20 to 25 years of age
  • Upper endoscopy screening

If colon cancer runs in your family, please seek counsel from your doctor. Communicating with your doctor will help you know your risk and ensure you have a colon screening at the appropriate time. Schedule regular visits with your doctor so you can have the best possible care.