No Cancer In Your Family...No Risk For You, Right?
Family history should 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 abnormal genes that are inherited (passed on from parents) and only 15-20% occur in a person with a family history (but no known genetic abnormality/mutation), therefore most cancers are actually 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 occurred in your family in the past.
It is also important to talk with older family members about cancer in the family. For many years, talking about cancer was taboo - in some cases it still is. You may not be aware of cancers in your family if they were never talked about. 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 uncover 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.
National Cancer Institute. 2017. The Genetics of Cancer. https://www.cancer.gov/about-cancer/causes-prevention/genetics