One aim of the NHS Long Term Plan is that 75% of cancers will be diagnosed at an early stage. This can be achieved through targeted screening and personalised surveillance of those most at risk of developing cancer, such as those with Lynch syndrome.
Each year, 1,100 colorectal cancers are caused by Lynch syndrome, making it the most common form of hereditary colorectal cancer. An estimated 175,000 people have Lynch syndrome in the UK, but fewer than 5% of individuals know they have the condition (Bowel Cancer UK).
Lynch syndrome is an inherited genetic condition caused by a germline pathogenic variant in one of four DNA mismatch repair (MMR) genes. Pathogenic variants in another non -MMR gene, known as EPCAM, can also cause Lynch syndrome.
The main concern in Lynch syndrome is colorectal (bowel) cancer. Around half of all people with Lynch syndrome develop colorectal cancer. For women, endometrial (womb) cancer is also a concern, and to a lesser degree ovarian cancer. There is small increase in the likelihood of developing a few other cancers: pancreatic, kidney, urinary tract, skin, brain and gastrointestinal cancers. However, these other cancers are seen only occasionally, and the increased risk is small – generally less than a 5% increase if you compare this risk to rest of the general population.
More information about Lynch Syndrome is provided below, together with information about testing and screening, action needed by cancer services, resources for health professionals (information for patients, standard operating procedures, management of the condition, implementing care pathways), as well as training videos and helpful websites.
The risk or likelihood of developing cancer depends on three factors: age, gender and which gene is implicated:
The likelihood of developing cancer is very low at an early age, including for people with Lynch syndrome. Cancer prevention bowel check-ups for people living with Lynch syndrome start at the age of 25-35. The likelihood of developing cancer increases with age, so people with Lynch syndrome will have bowel checks every two years.
Men tend to have a higher risk of developing colorectal cancer as compared to women. However, women have the additional risk of endometrial and ovarian cancer.
Different genes have a different likelihood of contributing to the development of cancer.
A child who has a parent with a pathogenic variant has a 50% chance of inheriting that pathogenic variant.
Since 2017, the National Institute for Health and Care Excellence (NICE) has recommended that all people with colorectal cancer are tested for Lynch syndrome and In October 2020, NICE also recommended testing for Lynch syndrome in people who are diagnosed with endometrial cancer
Implementing Lynch syndrome pathways nationally provides an opportunity to detect many of these cancers at an earlier stage. It may also help to prevent cancers through risk reduction treatments and appropriate surveillance programmes for patients, and their at-risk family members, who are not yet aware that they have Lynch syndrome and are at risk of developing cancer.
Furthermore, a diagnosis of deficient MMR (dMMR) can affect cancer treatment options, with certain tumours being more responsive to particular chemotherapy agents. People with Lynch syndrome are also responsive to new immunotherapy drugs. It is therefore important that the initial tumour test is done in time to inform treatment options.
If all people with colorectal cancer and their family members were tested for Lynch syndrome and enrolled into appropriate surveillance pathways in 2028, it could result in up to a 0.9%-point increase improvement in the proportion of cancers diagnoses early.
Testing for Lynch
It is not straightforward to find out if a cancer is inherited or sporadic (out of the blue). To find out if someone has an inherited cancer that is being passed down in the family, there are different tests that need to be performed. In addition to taking a detailed family history, for Lynch syndrome, some tests are performed on the cancer (tumour) sample. This is because Lynch syndrome leaves a fingerprint in the tumour.
The initial tumour tests are immunochemistry (IHC) and microsatellite instability (MSI):
- Immunochemistry (IHC). Every person diagnosed with colorectal or endometrial cancer should have IHC performed on their tumour. IHC looks at the expression of the proteins produced by these ‘mismatch repair’ genes. If there is a loss of expression of any of these proteins, patients may be offered genetic testing to find out if they have Lynch syndrome.
- Microsatellite Instability (MSI). This is another type of genetic test on the tumour to find out if the patient is likely to have Lynch syndrome. If the result is positive, they might have Lynch syndrome, and will be offered genetic testing.
Additional testing may be required using MLH1 promoter Hypermethylation (MLH1 Methylation). In some cases, following an IHC test, this test might be necessary to clarify if the cancer is sporadic and originates in the tumour cells, or if it could possibly be inherited. If the result of this test shows that the tumour sample is methylated, it clarifies that the cancer is sporadic and originates in the tumour. If not, it is possible that it might be Lynch syndrome and patients will be offered genetic testing.
Screening and risk-reducing strategies
There are important general screening recommendations and cancer prevention strategies for Lynch syndrome.
Aspirin (NICE guidelines 2020) from the age of 25 to 65 for cancer prevention: Aspirin has been shown to reduce the long term risk of cancer in Lynch syndrome by around 50%. Trials to determine the best dose of aspirin for cancer prevention are still ongoing, Lynch syndrome: should I take aspirin to reduce my risk of getting bowel cancer. Patient decision aid, NICE, 2020]
One-off screening for Helicobacter pylori: H. pylori is a bacteria that 30% of the population have in the stomach. Eradication of these bacteria may reduce the lifetime risk of gastric cancer by half.
General lifestyle recommendations: Healthy diet: High fibre, low fat, with plenty of fruit and vegetables, eating less red and processed meat.
Behaviours: Limiting alcohol intake, stopping smoking, and regular exercise all have a role in preventing the development of cancer.
Body weight: Maintaining a healthy body weight is also important.
Two-yearly colonoscopy: For colorectal cancer prevention.
Gynaecological surveillance: Currently there is limited evidence to support gynaecological surveillance for the early detection of gynaecological cancer in Lynch syndrome. There are some surgical risk-reducing interventions available for women between the ages of 40 and 45 who have completed their family.
To prevent or reduce the risk of developing other cancer types, education in recognition of early signs & symptoms
What do cancer services need to do?
1.All trusts should appoint an individual to take on responsibility for implementing this pathway. The Cancer Alliance has written out to all Colorectal & Endometrial Cancer MDTs asking them to nominate a ‘Lynch Lead.’ This lead is well placed to also champion implementation of the Lynch pathway across various specialties and the Alliance has also asked for other specialities, where we know Lynch may be implicated, to be part of pilot lynch test pathways.
2.Establish a regional Lynch network to support and develop the delivery of a cross-system service. Bring together key stakeholders (pathology, endoscopy, GLHs, clinical genetics service, cancer team, surgical team, Genomic Medicine Service Alliances and Cancer Alliances) bi-annually as part of a Lynch syndrome network to review delivery of service standards and to support service development.
3.Develop regional expert centres who will be able to provide clinical advice and training to dedicated local leads within cancer MDTs and manage regional patient registries.
4.Identify how you will ensure patient and carer feedback is welcomed, listened to and acted upon throughout the pathway as a measure of experience of care
5.Work with GPs to prepare for a rise in the number of people presenting and asking for a referral to the genetics service due to risk of Lynch syndrome. Make sure they are aware of referral pathways and who to signpost any questions on to.
To assist healthcare professionals in testing patients for Lynch syndrome, we have developed a bank of training videos and other resources kindly shared by others, these will;
- support Trusts across the East of England to improve delivery of their local diagnostic pathway for Lynch syndrome
- improve uptake of genetic testing for Lynch syndrome through integration into standard cancer clinics.
By providing these resources we hope to support clinicians, so they can identify and consent patients for genetic testing at the routine oncology appointments. Any clinician (i.e. surgeon, oncologist, or nurse specialist) involved in the care of patients can complete this training.
The training involves watching six short videos which cover all the different stages of the Lynch syndrome pathway. In addition, there is a range of supporting documents to help understand this pathway.
The training videos cover:
- Video 1: What is mainstreaming?
- Video 2: Overview of Lynch syndrome
- Video 3: Tumour testing: Identifying patients likely to have Lynch syndrome
- Video 4: Taking a genetic family history: Drawing a family pedigree
- Video 5: Genetic counselling & Genetic testing
- Video 6: Managing genetic results
The training presentations last for approximately 7-15 minutes each.
Module 1: Introduction (Introduction to mainstreaming cancer genetics)
Module 2: Lynch syndrome (Genetic testing for Lynch Syndrome)
Prospective Lynch Syndrome Database - calculation of cumulative risk for cancer
Insurance information for patients:
Insurance implications for family members that do not have cancer and are going to have a predictive genetic blood test are different. More information is available from Genetic Alliance UK.
Lynch Syndrome UK - a charity to help sufferers of Lynch Syndrome