About one in 18 (6%) Canadians will develop colon cancer in their lifetime. 5 to 10% of these cancers are associated with a hereditary predisposition. One condition, called Lynch syndrome, accounts for 2-4% of all diagnoses of colon cancer. There are several other well-known hereditary colon cancer syndromes that can be easily identified with a genetic test.
A pathogenic variant in the Lynch syndrome gene called MLH1is associated with a 40% to 60% risk of developing colon cancer during one’s lifetime. Lynch syndrome may also be associated with a predisposition to other cancers, such as uterine, ovarian, small intestine, stomach, and pancreatic cancers. We must therefore not underestimate the presence of different cancers in our family history even if they may seem unrelated. It is the role of a genetic counselor to help review your family history and clarify any myths or misconceptions you may have.
The presence of certain genetics in the family history, both maternal and paternal, increases the possibility of hereditary cancer:
- Colon cancer before the age of 50;
- More than one cancer in the same person;
- More than 2 family members with the same type of cancer;
- Ovarian or uterus cancer;
- Pancreatic cancer;
- Multiple colon polyps (benign in the colon)
Knowing if you are a carrier of a pathogenic variant in a gene predisposing to cancer gives you access to closer medical monitoring adapted to your genetic risks, early treatment, and risk reduction options.
Prevention is the key to health!