What is Lynch Syndrome?

Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC) is an inherited condition that runs in families and increases the risk of developing bowel cancer as well as other cancers. It is the most common cause of hereditary bowel cancers and accounts for between 2-5% of all bowel cancers. Up to 75 percent of people with Lynch syndrome will develop bowel cancer at some point in their lives and the average age of developing bowel cancer is younger than in the general population (below 50).

Other cancers that may develop if you have Lynch syndrome

As well as an increased risk of bowel cancer, people with Lynch syndrome are also at a greater risk of a number of other cancers including:

• Womb
• Stomach
• Ovarian
• Pancreatic
• Prostate
• Urinary tract
• Liver
• Kidney
• Bile duct

What causes Lynch syndrome?

Lynch syndrome is caused by a mutation in one or more of the following genes. If a person inherits an altered (mutated) copy of the gene, they are at higher risk of developing cancer.

• MLH1
• MSH2
• MSH6
• PMS2
• EPCAM

GeneHealth UK is able to offer genetic testing for all of these genes and others related to bowel cancer.

Indications that there may be Lynch syndrome in a family

1. Bowel cancer diagnosed at a young age (before the age of 50)
2. Bowel cancer that has screen positive* for Lynch syndrome
3. Several relatives with bowel cancer
4. Relatives with bowel cancer and related cancers (such as womb or ovarian cancer)
5. Multiple generations with cancer

Tumour testing*

It has now been recommended that all colorectal cancer should be screened for Lynch syndrome by performing tumour testing.  Tumour testing involves performing immunohistochemistry (IHC) and microsatellite instability (MSI) to see if the cancer may have been caused by Lynch syndrome. If tumour testing screens positive, then further testing on a blood sample is recommended.

Reducing risk and early detection

Diagnosing Lynch syndrome early is important as it allows for cancer screening from an earlier age and, in some cases, offered surgery or medication can help reduce the risk of developing cancers associated with this condition. As with all cancers, early detection saves lives.