Abramson Cancer Center of the University of Pennsylvania
Last Modified: March 23, 2012
Family history is always part of a cancer risk discussion. Many people believe that having no one in the family with cancer means they have no cancer risk. In reality, only 5-10% of cancers are caused by inherited factors (abnormal genes) and 15-20% occur in a person with a family history (but no known genetic abnormality/mutation), therefore most cancers are not related to family history. For example, 80% of people diagnosed with colorectal cancer have no family history of the disease at all. This is not meant to scare people, but to serve as a reminder that reducing cancer risk and cancer screening is important for everyone, even when cancer has not affected a family in the past.
It is also important to talk with older family members about cancer in the family. For many years, discussion of cancer was taboo. You may not be aware of cancers in your family if they were never discussed. Relatives may not know exact diagnoses, but they may remember that Aunt Mary had a "basketball in her belly" or "stomach problems", which could have been a tumor, perhaps ovarian, stomach or colon. It takes a bit of detective work to discover family history, so at the next family gathering, start asking questions and see what you uncover. Use My Family Health Portrait to create a family health history.