Lynch Syndrome Testing: Who Qualifies on the NHS?

If bowel or womb cancer runs in your family, you may have heard of Lynch syndrome. It’s one of the inherited conditions doctors consider, particularly when cancer develops at a younger age or different related cancers occur in the same family.

What is Lynch syndrome?

Lynch syndrome is the most common inherited cause of bowel cancer in the UK. It’s estimated to be responsible for around 3% of bowel cancers, but many people who carry the condition don’t know they have it.

Lynch syndrome is caused by an inherited change in a gene that normally helps repair mistakes in our DNA. When that repair system doesn’t work properly, the risk of developing certain cancers increases.

Bowel cancer is the best-known risk, but Lynch syndrome can also increase the risk of womb (endometrial) cancer, ovarian cancer and some other cancers.

You are born with Lynch syndrome, but that doesn’t mean you will develop cancer. The level of risk depends partly on which gene is affected, and there are important steps that can help reduce that risk.

Can Lynch syndrome come from either parent?

Yes. Lynch syndrome can be inherited from your mum or your dad, and each child of someone with Lynch syndrome has a 50% chance of inheriting the genetic change.

Importantly, your parent doesn’t need to have had bowel cancer to pass Lynch syndrome on to you.

Some people who carry the genetic change never develop cancer. Others may have developed a different cancer, such as womb cancer, rather than bowel cancer.

This is one reason why looking only for bowel cancer in your family history can miss people with Lynch syndrome.

How does NHS genetic testing for Lynch syndrome work?

If someone is diagnosed with bowel cancer or womb cancer, the NHS should offer testing of their tumour to look for signs of Lynch syndrome.

There are two stages of testing, and understanding the difference is important.

1. Testing the cancer itself

The first step usually involves checking a sample of the cancer that has already been removed or biopsied.

Doctors look for signs that the cancer’s DNA repair system isn’t working properly. You might see these results described as:

• dMMR (deficient mismatch repair): A test showing that certain proteins responsible for repairing DNA are missing from the tumour.
• MSI-high (microsatellite instability): A test showing a pattern of DNA changes that can occur when the repair system isn’t working properly.

These findings can suggest Lynch syndrome, but they don’t automatically mean the person has an inherited condition.

Some cancers develop these changes during a person’s lifetime without an inherited cause.

Depending on the tumour results, the laboratory may carry out additional tests to help decide whether inherited testing is needed.

2. Testing for an inherited genetic change

If the tumour results suggest Lynch syndrome, the patient may be referred for inherited genetic testing, also called germline testing.

This usually involves a blood or saliva sample and looks for inherited changes in genes such as MLH1, MSH2, MSH6 and PMS2, or changes involving EPCAM.

Unlike tumour testing, inherited genetic testing can tell us whether someone carries a change that may also affect their relatives.

Why does this matter?

If Lynch syndrome is confirmed, family members can be offered testing for the same genetic change. Those who have inherited it can then access appropriate screening and prevention, potentially long before any cancer develops.

Someone with a strong family history or a known genetic change in the family may also be referred for genetics assessment even if they haven’t had cancer themselves.

Does a history of bowel polyps matter?

Yes, although most bowel polyps aren’t caused by an inherited condition.

Polyps are small growths that develop on the lining of the bowel. They’re often found during a colonoscopy, which is a camera examination of the large bowel.

Most polyps aren’t cancerous, but some can develop into bowel cancer over time. This is why they’re usually removed when they’re found.

Having one or two polyps is relatively common, particularly as we get older, and doesn’t necessarily suggest an inherited cancer risk.

However, having lots of polyps, developing them at a young age or having several relatives with multiple polyps can sometimes indicate an inherited condition.

For example, familial adenomatous polyposis (FAP) is an inherited condition that can cause large numbers of bowel polyps, sometimes beginning in the teenage years.

FAP is different from Lynch syndrome, but both are important inherited causes of bowel cancer risk.

If you’ve had multiple bowel polyps, it’s worth telling your doctor how many were found, how old you were and whether anyone else in your family has had similar problems.

Can I qualify for a colonoscopy because of my family history?

Yes. And this is something many people don’t realise.

You don’t necessarily need to have Lynch syndrome, or even have genetic testing, to qualify for additional bowel cancer screening on the NHS.

The British Society of Gastroenterology (BSG) has guidelines for people whose family history puts them at increased risk of bowel cancer.

For example:

• If your mum, dad, brother, sister or child developed bowel cancer before 50, you may be considered at moderately increased risk. The BSG recommends a one-off colonoscopy at age 55.
• If two first-degree relatives have had bowel cancer, you may also qualify for additional assessment and a colonoscopy at 55, depending on how the relatives are related.
• If several close relatives across different generations have had bowel cancer, you may fall into a higher-risk group. For families meeting the BSG high-risk criteria, colonoscopy is recommended every five years from age 40 until 75.

These are examples rather than a complete list, and the exact relationships and ages matter.

Importantly, you may benefit from additional screening even when no inherited gene change has been identified.

If bowel cancer runs in your family, ask your GP whether your history meets the criteria for referral to a specialist family history or gastroenterology service.

And if you’ve already had bowel polyps, your doctor may recommend a different surveillance schedule based on the number, size and type of polyps found.

What should I ask my GP?

If bowel cancer or womb cancer runs in your family, it’s worth asking your GP whether there could be an inherited risk.

You don’t need to know the names of genetic conditions or have a perfect family tree before asking for advice.

You could simply say:

“Several people in my family have had bowel or womb cancer, and I’m wondering whether it could be inherited. Would genetic testing be useful for our family?”

If a relative has already been diagnosed with bowel cancer or womb cancer, it’s also worth finding out whether their tumour was tested for Lynch syndrome.

Try to bring along:

• Which relatives have had cancer, including relatives on your dad’s side.
• What types of cancer they had, especially bowel, womb or ovarian cancer.
• Roughly how old they were when diagnosed.
• Whether anyone has had multiple bowel polyps or more than one cancer.
• Any previous genetic testing results in the family.

Your GP can help assess whether an NHS clinical genetics referral would be appropriate.

And remember, not everyone with Lynch syndrome has an obvious family history. Sometimes the first person in a family to be diagnosed is identified through genetic testing.

Even if you don’t qualify for genetic testing, it’s worth asking whether your family history means you should have a colonoscopy earlier than usual.

You could simply ask:

“Does my family history put me at increased risk of bowel cancer, and should I be referred for earlier colonoscopy screening?”

The answer may depend on how many relatives have had bowel cancer, their ages when diagnosed and how they’re related to you.

What changes if Lynch syndrome is confirmed?

Finding out you have Lynch syndrome can be frightening, but it also gives you the opportunity to take action.

We now know much more about how to reduce cancer risk in people with Lynch syndrome, and there are several important options.

Earlier and more frequent bowel screening

People with Lynch syndrome are usually offered regular colonoscopies through a specialist NHS surveillance programme.

Depending on which gene is affected, this can begin as early as 25 years old, with colonoscopy generally repeated every two years.

A colonoscopy allows doctors to find and remove polyps before they become cancerous, or identify cancer at an earlier stage when treatment is more likely to be successful.

Aspirin can significantly reduce bowel cancer risk

This is one of the most important developments in Lynch syndrome prevention.

Research has shown that taking aspirin regularly for at least two years can substantially reduce the long-term risk of bowel cancer in people with Lynch syndrome.

In the CAPP2 trial, people who took aspirin for at least two years had approximately half the risk of developing bowel cancer during longer-term follow-up compared with those taking placebo.

NICE recommends considering daily aspirin for people with Lynch syndrome.

However, aspirin isn’t suitable for everyone, and the dose needs to be discussed with a doctor because of potential side effects, particularly bleeding and stomach ulcers.

Don’t start taking aspirin for cancer prevention without first discussing it with your GP or specialist.

Reducing the risk of womb and ovarian cancer

Lynch syndrome can also increase the risk of womb and ovarian cancer, although the level of risk varies considerably depending on which gene is affected.

For some women, surgery to remove the womb, and sometimes the ovaries and fallopian tubes, may be an option to reduce future cancer risk.

These are very personal decisions. Your age, family plans, menopause and the particular genetic change all matter, so they should be discussed with a specialist team.

Testing other family members

Once a specific inherited genetic change has been identified, adult relatives can usually be offered a targeted test to find out whether they carry it too.

This can help identify family members who would benefit from earlier screening, while also providing reassurance to relatives who haven’t inherited the familial change.

Support with making decisions

You don’t have to work through these decisions alone.

Lynch Choices is an excellent UK resource to help people with Lynch syndrome understand their options, including aspirin, cancer screening and risk-reducing surgery.

Lynch Syndrome UK also provides information, practical support and opportunities to connect with other people living with Lynch syndrome.

Finding out you have Lynch syndrome isn’t simply about knowing you’re at higher risk. It’s about having more opportunities to prevent cancer or find it earlier.

Genetic testing referrals for healthcare professionals

If you’re a gastroenterologist, colorectal surgeon, endoscopist or other healthcare professional caring for patients concerned about inherited bowel cancer risk, we can help.

Colonoscopy is an essential part of bowel cancer prevention, but it doesn’t tell us whether someone carries an inherited cancer-risk gene.

And while NHS pathways provide important access to genetic testing, not everyone who might benefit from understanding their inherited risk meets the eligibility criteria.

At Coyne Medical, we already work with consultants who want to offer genetic testing as part of the care they provide.

Our comprehensive 36-gene inherited cancer panel includes the key genes associated with Lynch syndrome (MLH1, MSH2, MSH6, PMS2 and EPCAM), as well as genes linked to other inherited bowel cancer conditions.

Every patient has a doctor consultation before testing and a scheduled follow-up appointment, whether their result is positive or negative.

We can help patients understand their results, discuss screening and cancer prevention, and coordinate NHS or private specialist referrals where appropriate.

With the patient’s consent, we can also share results and recommendations with their referring clinician.

We work alongside you, helping you offer your patients more comprehensive preventative care.

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What should you do if bowel cancer runs in your family?

If someone in your family has had bowel cancer, particularly at a younger age, or you’ve noticed several cases of bowel or womb cancer, it’s worth finding out whether there could be an inherited risk.

Start by checking who may qualify for NHS genetic testing.

It can also help to collect some information about your relatives’ diagnoses and their ages at the time. Our guide to understanding your family history of cancer explains what to look for.

But remember, you don’t need a family history of cancer to carry an inherited cancer-risk gene. Some people with Lynch syndrome have no obvious family history at all.

Finding risk earlier creates choices

At Coyne Medical, we believe understanding inherited cancer risk can help people take control of their future health.

Our doctor-led 36-gene inherited cancer panel includes genes associated with Lynch syndrome and other inherited bowel cancer conditions.

We offer consultations before and after testing to explain your results, discuss ways to reduce your risk and help arrange further screening or specialist referrals when appropriate.

Even if genetic testing doesn’t identify an inherited change, we can help you understand what your family history might mean for your health.

Clinical references

NICE DG27 colorectal: https://www.nice.org.uk/guidance/dg27

NICE DG42 endometrial: https://www.nice.org.uk/guidance/dg42

NHS Genomic Test Directory: https://www.england.nhs.uk/publication/national-genomic-test-directories/

Information prepared 28 October 2026. This page is for general information, not personal medical advice or a consultation. Discuss your family history, personal screening and medical decisions with your own doctor or healthcare team. NHS pathways and criteria may change and differ across UK nations.