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Lynch Syndrome (also known as hereditary non-polyposis colorectal cancer or HNPCC) is a rare condition that may cause a family history of bowel cancer. Conditions that run in families are known as familial or hereditary.
The term non-polyposis differentiates it from another condition called FAP (familial adenomatous polyposis), where hundreds of polyps (small growths) develop in the bowel.
Lynch Syndrome is the most common cause of hereditary bowel cancer. Fewer than 5 in 100 (5%) of all bowel cancers are linked to Lynch Syndrome. Women with Lynch Syndrome also have an increased risk of developing womb (endometrial) cancer.
There is also a slight increase in risk of developing cancer of the ovaries. People with Lynch Syndrome also have an increased risk of stomach, pancreas, biliary and bladder cancers.
Knowing about risk and having regular screening may help prevent some cancers and detect others in the early stages when they're curable.
Lynch Syndrome is caused by a fault in one of the genes known as the 'mismatch repair' genes. These particular genes normally work to help prevent you getting cancer.
Lynch Syndrome may be suspected in families with close blood relatives who have developed bowel, womb and ovarian cancer over several generations. We have two copies of each gene – one from each of our parents. If someone has Lynch Syndrome it means they have a healthy gene but also one that's faulty.
If that person has a child there is a fifty–fifty chance that they will pass on the faulty gene (only one copy of a gene is passed on from each parent). This called autosomal dominant inheritance.
They may have inherited a faulty copy of one of the DNA ‘mismatch’ repair genes. Four of the mismatch repair genes (known as MLH1, MSH2, MSH6 and PMS2) are responsible for most cases of Lynch Syndrome. So, if a person inherits a faulty copy of one of these genes, it increases their risk of developing bowel cancer and the other types of cancer we've already mentioned.
Lynch Syndrome is more likely if there are lots of cases of bowel and womb cancer on one side of the family and if they were diagnosed at an early age. However, not everyone with Lynch Syndrome has a family history of it. This is because some people may be the first in their family to get it.
Lynch Syndrome may be suspected if:
If you're worried about cancer in your family, speak to your doctor who can refer you to a family cancer clinic.
Lynch Syndrome itself doesn't cause any symptoms. It's an inherited syndrome that means a person has a higher risk of developing bowel and womb cancer.
Sometimes the first sign that a person has Lynch Syndrome is when the symptoms of bowel or womb cancer develop. This generally happens at a younger age than people whose cancers aren't due to an inherited faulty gene. And there's usually a history of these cancers in the family.
Bowel cancer that doesn't run in families usually develops in people over 50, but in Lynch Syndrome, bowel cancer usually occurs between the ages of 40 and 50 or younger.
Being aware of your normal bowel habit is important, particularly if you have or think you may have Lynch Syndrome.
If you have any of the following symptoms it's important to get them checked out by a doctor:
It's also important to be aware of the symptoms of womb cancer if you have or think you may have Lynch Syndrome. Any of the following symptoms should be checked out by a doctor:
All these symptoms can be caused by conditions other than cancer, but it's always important to get them checked by your doctor.
It's possible to find out if someone has Lynch Syndrome by doing a genetic test. This test is first carried out on the family member who has had cancer. If the faulty Lynch Syndrome gene is found in that person, then close family members (not affected by cancer) can be tested (if they wish) to see if they have inherited it.
Testing the Tumour
If a person has a suspected Lynch Syndrome-type cancer, before genetic testing, a special test may be done on a tissue sample taken from the tumour. If this is positive, genetic testing is offered. It may also guide us in the type of screening you may need over your lifetime.
Genetic testing is only carried out if a person is willing to have it. All that's needed is a blood sample, but it can take a while (up to a year) to get results as the genes are large and the faulty gene may be difficult to find.
Once the faulty gene has been found, other family members can then be tested for the same faulty gene.
Before genetic testing, a person will have counselling to help them understand the results and what they mean for them and their family.
Sometimes the faulty gene can't be found in the person with the Lynch Syndrome type of cancer (because it's not Lynch Syndrome or there's a fault in the gene that research hasn't yet identified). If no gene change is found other family members can't be tested. However, based on their family history, they can still have regular bowel tests and womb checks (in women) to reduce their cancer risk.
What the test results mean:
Knowing your risk of cancer means you can have regular tests (screening). Bowel cancers can be curable when they're picked up early.
If a person is found to have inherited the faulty gene, they will usually be advised to have regular bowel screening from a young age. This may begin at the age of 25. Some women may also be offered screening for womb cancer.
If the faulty gene wasn't found in the person with Lynch Syndrome-type cancer, it's important that you still have screening as you may still be at risk of cancer. This is the same if you decided against genetic testing or couldn't have it because a family member with Lynch Syndrome-type cancer didn't want a test.
Colonoscopies may be performed every 2 years from the age of 25 years in the outpatient endoscopy unit. This screening is proven to significantly reduce your risk of developing bowel cancer, by as much as 72%.
Some people with Lynch syndrome and a history of stomach (gastric) cancer may also have a regular gastroscopy performed from a later age.
We don't yet know if womb screening in women with Lynch Syndrome is helpful. You may ask your GP to refer you to our Gynaecology Department for further advice.
The womb can be screened using a procedure called a hysteroscopy or by using a vaginal ultrasound. Your doctor or nurse will explain which test you will have. During a hysteroscopy a thin, flexible tube with a light at the end will be used to look inside the uterus. A vaginal ultrasound scan involves putting a small device that makes sound waves into the vagina. The sound waves are then converted in to a picture by a computer.
We don't know if ovarian screening helps pick up ovarian cancer at an earlier stage. Occasionally some women may be offered it or they may have it done as part of a research trial.
The risk of developing ovarian cancer if you have Lynch Syndrome is much lower than your risk of bowel or womb cancer. Screening can involve a blood test, a vaginal ultrasound or both. The blood test checks the levels of a protein called CA125.
Aspirin and risk reduction in Lynch Syndrome
Recently the results have been published of a trial of the role of aspirin in the prevention of cancer in patients with Lynch Syndrome. Aspirin taken at 600mg once daily for 2 years from approximately the age of 45 years may reduce the risk of bowel and all other Lynch syndrome associated cancers by over 50%. Whether this is the right thing for you or not is something you should discuss with your GP.
If you develop bowel cancer, it's likely to be picked up early through having regular colonoscopies. Any Lynch Syndrome-type cancer is treated in the standard way for that type of cancer.
Treatment for bowel cancer will usually involve surgery to remove the cancer. Further treatment with chemotherapy might be needed, depending on the stage of the cancer.
Treatment for womb cancer will usually involve removing the womb (hysterectomy) and the ovaries. Radiotherapy may also be given.
Risk-reducing surgery Occasionally with Lynch Syndrome, it's recommended that the whole of the large bowel is removed as a preventative measure. This is known as risk-reducing surgery. It's usually only recommended where the risk of developing cancer is thought to be very high or if a person with Lynch Syndrome develops more than one bowel cancer.
Some women (when they've completed their families) may choose to have their womb and ovaries removed to reduce their risk of womb and ovarian cancer.
Knowing that you have Lynch Syndrome or are at risk of it can be very difficult to cope with. The uncertainty of not knowing if you will develop cancer isn't easy to deal with, but it's important to remember that bowel cancer can be found early and cured. You may have concerns about genetic testing, screening or whether you should have risk-reducing surgery.
It's important to talk these concerns over with the doctors and nurses caring for you. They'll be happy to answer any questions you have.
You may have many different emotions, including anxiety and fear. These are all normal reactions and are part of the process that many people go through in trying to come to terms with their condition.
Many people find it helpful to talk things over with their doctor or nurse. Close friends and family members can also offer support.
Further Information
http://www.library.wmuh.nhs.uk/pil/colon%20cancer.htm
Email: bowelcancer@wmuh.nhs.uk
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