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Is bowel cancer in your genes?

Bowel Cancer Australia

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Lynch syndrome, also known as HNPCC (Hereditary Non-Polyposis Colorectal Cancer) is an inherited genetic mutation which puts people at increased risk of developing one or more often-aggressive primary cancers in their lifetime.

It is the most common form of hereditary bowel cancer and is caused by a fault in a gene (known as the 'mismatch repair' gene) that normally functions to protect a person from getting cancer.

Lynch syndrome can affect treatment options offered to those diagnosed with bowel cancer, so screening for the genetic fault should be performed at the time of bowel cancer diagnosis.

Genetic testing of tumours for Lynch syndrome is now recommended for all bowel cancer patients, especially those age 70 and below.

If a person is diagnosed with Lynch syndrome, their parents, children, and siblings have a 50% chance of also carrying the gene.

Other blood relatives including grandparents, aunts, uncles, nieces and nephews are also likely to be carriers.

The patient and their family can be referred for genetic testing to find out if they are affected.

Identifying people that are carriers of Lynch syndrome allows for early and increased surveillance, the option of preventative surgery and the ability to determine increased cancer risk in the extended family.

According to a new health report released by Lynch Syndrome Australia this week, more than 80,000 Australians are unaware that they carry the ‘faulty’ gene.

Where Lynch syndrome is suspected in your family, your GP or specialist will refer you to a Family Cancer Clinic for support and ongoing management of the condition.

People with Lynch syndrome and those that may be carriers should immediately tell their GP about any possible bowel cancer symptoms.

The risk of developing bowel cancer in people with untreated Lynch syndrome ranges from 70 – 90%.

In families where there is a clear history of Lynch syndrome, screening with colonoscopy every 1 to 2 years usually begins at age 25, or 5 years earlier than the youngest relative diagnosed, whichever comes first.

Regular surveillance by colonoscopy has been shown to reduce incidence and mortality of bowel cancer in Lynch syndrome patients and in affected family members.

It is important to note that a diagnosis of Lynch syndrome can have a major impact on the life of those affected and their family.

As well as the need to keep up regular surveillance there can be medical, emotional and financial ramifications.

The option to undertake genetic counselling is an important consideration and one that is recommended for anyone considering genetic testing for Lynch syndrome, in order to work through issues such as future insurance and the possibility of passing the faulty gene on.

If you have any questions about Lynch syndrome or other genetic mutations https://www.bowelcanceraustralia.org/genetics please feel free to contact our Bowel Care Nurses on 1800 555 494 or send us an email.

Download our infographic to find out if bowel cancer is in your genes.