An estimated 900 Australians diagnosed with bowel cancer each year, many of them under age 50, will have an underlying genetic cause.
Lynch syndrome is the most common genetic condition that increases a person’s risk of developing bowel cancer.
It is caused by a change in a gene (the mismatch repair gene) that normally functions to protect a person from getting cancer.
Lynch syndrome can affect the best choice of treatment options for bowel cancer patients, and also has preventative health and screening implications for family members.
In celebration of International Lynch Syndrome Awareness Day (22 March), Bowel Cancer Australia encourages all Australians to better understand their bowel cancer family history and for all newly diagnosed patients to speak with their treating specialist about having their tumour tested for mismatch repair deficiency as a means to subsequently identify Lynch syndrome.
The bowel cancer risk in someone with Lynch syndrome is hundreds of times greater than the average.
But less than 5% of patients affected are aware of their risk because a simple test that could indicate the gene mistake is not being conducted.
“Anyone who is diagnosed with bowel cancer could be harbouring a genetic inheritance without knowing it,” Bowel Cancer Australia’s Community Engagement Manager Claire Annear said.
All bowel cancer patients, and particularly those diagnosed under the age of 50, should speak to their treating specialist about having their tumour screened for indicators of Lynch syndrome.
“The simple test helps ensure loved ones are aware of any possible risk, and able to then seek genetic counselling and testing if needed.” Ms Annear added.
Bowel Cancer Australia aims to empower patients with the knowledge and tools required to be advocates for their own health.
The 'Is Bowel Cancer in Your Genes?' infographic serves as a timely reminder to talk to loved ones about family history and genetic risk factors.
If you have any questions about bowel cancer and family history or genetic inheritance, contact Bowel Cancer Australia's team of friendly Bowel Care Nurses.
| What is Lynch syndrome
Lynch syndrome (previously known as HNPCC - Hereditary Non-Polyposis Colon Cancer) is an inherited genetic mutation which gives people an increased risk of developing certain types of cancers throughout their lifetime, including bowel cancer.
Every person inherits genes from both their parents and Lynch syndrome is caused by a fault in a gene that normally functions to protect a person from getting cancer (known as the 'mismatch repair' genes). The 'faulty' gene increases a carrier’s risk of developing bowel cancer and other types of related cancers e.g. some gynaecological cancers, digestive tract, urinary tract or brain cancer.
Where it runs in a family, Lynch syndrome can present itself as many different cancers across multiple family members.
Particularly where those family members are diagnosed at a younger than average age.
If left untreated, the risk of developing bowel cancer in people with Lynch syndrome is 70-90 per cent.
Around 30 per cent of bowel cancer patients have a family history or genetic inheritance, both of which significantly increase a person’s risk of developing bowel cancer.
If a person is diagnosed with Lynch syndrome their parents, children, and siblings have a 50% chance of having the condition.
Other blood relatives (grandparents, aunts, uncles, nieces and nephews) are also at increased risk.
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.
| Lynch syndrome and bowel cancer
People with Lynch syndrome are much more likely to develop bowel cancer, especially at a younger age.
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 diagnosis.
The latest clinical practice guidelines for the prevention, early detection and management of bowel cancer recommend universal testing of all bowel cancers for Lynch syndrome.
In spite of this, with the exception of Western Australia, the test is not routinely offered to all patients in all Australian States and Territories.
Being tested for Lynch syndrome early in a bowel cancer diagnosis can help a patient's family find out if they carry the faulty gene as soon as possible and take steps to lower their risk.
A simple screening test can be carried out on a patient's bowel cancer tumour tissue to identify if they are likely to have Lynch syndrome. If the screening test is positive the patient and their family can be referred for genetic testing.
You are your own best advocate.
If you have been diagnosed with bowel cancer, ensure your treating specialist performs the test that could help determine if your cancer may have been genetically inherited.
| Screening and surveillance
Bowel cancers in Lynch syndrome can develop much more quickly than those in the general population. But there is much that can be done to reduce the cancer risk in someone carrying the genetic mutation.
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.
Regular screening by colonoscopy has been shown to reduce both the incidence and mortality of bowel cancer in Lynch syndrome patients and affected family members.
According to medical guidelines, surveillance colonoscopy every 1 to 2 years is recommended if you carry a germline mutation or are clinically at risk of carrying a mutation but definitive testing is not possible, commencing from age 25 or 5 years earlier than the youngest affected family member if they were diagnosed under 30, whichever comes first.
Where Lynch syndrome is suspected in your family, your GP 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 at risk should immediately tell their GP about any possible bowel cancer symptoms.
| Genetic testing
Genetic testing looks for specific inherited changes (mutations) is a person’s chromosomes, genes, or proteins.
Some mutations can be harmful and may increase a person’s risk of developing cancer.
Genetic testing can confirm whether a condition, such as bowel cancer, is the result of an inherited syndrome. It can also help to determine whether family members without obvious illness have inherited the same mutations.
The best indicator of being at risk of bowel cancer is having a close relative who has bowel cancer, especially if they were diagnosed before 55 years of age.
Wherever possible, screening of tumour tissue from the bowel cancer patient should be completed first to help determine which gene is likely to be affected and if further genetic testing is appropriate.
These initial screening tests are looking for changes in the genetic information within the cancer cell and include Microsatellite instability (MSI) testing and Immunohistochemistry (IHC) testing.
If the family-specific gene mutation can be identified, other at-risk relatives can have a blood test to see if they have inherited the same mutation.
Genetic testing in Australia is arranged through Family Cancer Clinics, where professionals make sure that people receive all the support and help they may need to make decisions about testing.
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 repercussions, implications for future insurance, and difficult decisions regarding the possibility of passing the faulty gene on to future children.
The option to undertake genetic counselling is an important consideration, and one that is recommended for anyone considering genetic testing for Lynch syndrome.
| Bowel cancer . . . you’re never too young
The average age of onset for bowel cancer in people with Lynch syndrome is 40-50 years, as compared to 60-70 years amongst the general population.
Bowel Cancer Australia therefore recommends that all bowel cancer patients diagnosed under the age of 50 speak to their treating specialist about having their tumour screened for loss of expression of mismatch repair protein (an indicator of Lynch syndrome).
Routine screening not only helps to determine if a patient is at greater risk of cancer recurrence, it also helps to identify family members who may have the condition and be at risk of bowel cancer at a younger age too.
| Sarah’s Story
My name is Sarah I’m now 36 but I was diagnosed with bowel cancer back in May 2016 when I was 33! I am a mother of four children my youngest at the time was 2 and my eldest was 6.
One Monday I was having terrible stomach pains my hubby was at work and I went to the doctors; my mum met me there as I was really struggling trying to coordinate 2 toddlers in a waiting room while in so much pain. I saw the doc and he sent me straight to hospital where they proceeded to do a laparotomy.
They thought it was a gynaecology problem but once in there they realised that everything was healthy there they then called in the bowel surgeons who proceeded to tell me when I came out that I had a bowel infection and that I probably had diverticulitis and needed to change my diet.
For the following 3 weeks I was back and forth from my doctor as I felt like I had a bladder infection. The doctor kept saying it’s the infection pushing on your bladder.
Finally, at the 3-week mark he referred me to a surgeon. Who then suggested I have a colonoscopy. I’ve had irritable bowel syndrome for years and they have checked every type of bowel issue but never a colonoscopy.
That was the day - I came out of surgery and he gave me the news right away. My hubby came in and I was a mess. I thought that was it! However, I had four babies at home that needed me.
I then had all the scans under the sun and yes it had spread. To my bladder and uterus. So, I then had surgery to remove the tumour. I had 300mm of my bowel removed I lost my bladder, uterus, 1 ovary and appendix.
I then went through nine months of chemo and 12 rounds – I was smashed! It made me very ill. I lost 14kgs in a week. However, I made it through the other end. My husband was amazing I don’t know what I would have done without him.
I then found out it was genetic! I have Lynch syndrome. No history of bowel cancer. After having genetic testing done, I have helped a lot of family members find out they to also have Lynch syndrome.
