At your next large family gathering, talking about past cancer diagnoses throughout the family tree could provide valuable insight about possible risks of inherited cancers. Researchers who study patterns of cancers within families are learning that—despite medicine’s technological advancements—a person’s family history of cancer continues to play a vital role in understanding hereditary cancers.
While all cancers originate with some genetic change or mutation within the body, a certain percentage of these mutations are inherited. The rest occur spontaneously, and environmental factors seem to play a major role. However, even for families who share a gene variant linked to cancer, it’s important to know that having the variant does not guarantee that a person will develop cancer; it does, however, put the person at a greater risk of developing the disease.
One of the strongest indicators of inherited cancer, also called hereditary cancer syndrome, is the patient’s age at the time of diagnosis. For example, a diagnosis of colon cancer at age 35 is much stronger evidence for an inherited cancer than a diagnosis at age 85. If you know that cancer runs in your family, it’s important to schedule an appointment with your doctor so he or she can evaluate you for referral to a cancer genetics program where, along with genetic testing, they will advise on cancer preventive measures according to your risk. For example, a young person who has a gene variant associated with a greater risk of colon cancer should receive a colonoscopy much earlier than age 45, which is the age the American Cancer Society suggests.
“We know that even if you have genetic mutations that give you a high risk of cancer, environmental factors can modify that risk quite a bit,” says gastroenterologist Xavier Llor, MD, PhD, who is co-director of the Smilow Cancer Genetics and Prevention Program. “Lifestyle modifications can actually help prevent the development of that cancer. This is true more so in patients who have these mutations than in those who don’t.” As an example, Dr. Llor says, a patient who loses just 5 percent of his or her body weight can significantly reduce cancer risk.
At Yale Medicine, the team of specialists at the Smilow Cancer Genetics and Prevention Program work to provide patients accurate risk assessment, genetic testing, and access to screening and cancer preventive measures.