One of the most common errors seen in the field of cancer genetic counseling is that people who have a personal and/or family history suggestive of Lynch syndrome are mistakenly tested only for BRCA1 and BRCA2.
In one such case, two sisters diagnosed with early-onset ovarian cancer tested BRCA negative and were told “lightning struck twice”. It wasn’t lightning, it was Lynch syndrome. A detailed family history revealed that the sisters had multiple family members with cancers of the uterus, gastrointestinal and urinary tracts. Important message here: be sure that a certified genetic counselor is assessing your case before you have genetic testing to ensure that the correct tests are ordered, and after your testing so that your results are interpreted accurately.
Lynch syndrome is a hereditary cancer syndrome that can be caused by mutations in one of at least five different genes. People with Lynch syndrome are at increased risk to develop colorectal, uterine and ovarian cancers, as well as other cancers of the gastrointestinal and urinary tracts. They are also more likely to be diagnosed with cancer at younger ages (often before age 50) than are other people in the general population, and their risk to develop more than one of these cancers is increased. Skin findings such as sebaceous adenomas and carcinomas can also occur.
Lynch syndrome affects both men and women and can be passed down through generations in a family. Luckily, genetic counseling and testing are available. When we know that a person has Lynch syndrome, they can be offered early and more aggressive surveillance, medications and surgeries that can reduce their risk of ever developing cancer.
If any of the following factors have been seen in your personal and/or family history, you may wish to explore your options for genetic counseling and testing for the genes involved in Lynch syndrome:
- Early-onset colon or uterine cancer (under <50 years)
- Clusters of colon, uterine, ovarian, biliary or urinary tract cancers on the same side of the family
- One family member who has developed multiple, primary (new) colon, uterine, ovarian or urinary tract cancers
- Sebaceous carcinomas/adenomas, especially in the context of a personal or family history of any of the above cancers
- Any Lynch syndrome-related tumor (most likely, colorectal or uterine) tumor that is MSI or IHC abnormal. If a tumor comes back MSI or IHC normal and you have a strong family history of cancer, genetic counseling should still be pursued.
Photo by Matthias Ripp, via Flickr