Quality standard

Quality statement 1: Testing for Lynch syndrome

Quality statement 1: Testing for Lynch syndrome

Quality statement

Adults with a new diagnosis of colorectal cancer have testing for Lynch syndrome. [new 2022]

Rationale

Lynch syndrome is an inherited condition that increases the risk of developing some cancers, including colorectal cancer. A large proportion of people in the UK with Lynch syndrome will be unaware that they have the condition. When adults are first diagnosed with colorectal cancer, testing for mismatch repair proteins on tumours using immunohistochemistry (IHC) or testing for microsatellite instability using polymerase chain reaction (PCR) can guide further testing (including BRAF V600E mutation testing and MLH1 promotor hypermethylation testing) to identify those in whom the cancer may have occurred because of Lynch syndrome. Testing can also inform systemic therapy choices for adults with colorectal cancer. For some cancer sites, risk-reducing strategies can prevent associated cancers or allow their early diagnosis in people with a diagnosis of Lynch syndrome. Testing for Lynch syndrome and offer of cascade testing for family members are included in the 2022/23 priorities and operational planning guidance from NHS England.

Quality measures

The following measures can be used to assess the quality of care or service provision specified in the statement. They are examples of how the statement can be measured, and can be adapted and used flexibly. The process measures follow the testing outlined in NICE's diagnostics guidance on molecular testing strategies for Lynch syndrome in people with colorectal cancer.

Structure

Evidence of local arrangements to ensure that there is a clinical lead responsible for implementing the testing pathway for Lynch syndrome.

Data source: Cancer Alliances in England have a record of the clinical lead responsible for implementing the testing pathway for Lynch syndrome within regional cancer multidisciplinary teams.

Process

a) Proportion of adults with a new diagnosis of colorectal cancer who had IHC for mismatch repair proteins or microsatellite instability testing on the tumour.

Numerator – the number in the denominator who had IHC for mismatch repair proteins or microsatellite instability testing on the tumour.

Denominator – the number of adults with a new diagnosis of colorectal cancer.

Data source: The National Disease Registration Service collects data on IHC for mismatch repair proteins and microsatellite instability tests and results from pathology laboratories and genomic laboratory hubs. The National Bowel Cancer Audit collects patient-level data on performance of mismatch repair protein and microsatellite instability tests.

b) Proportion of adults with a new diagnosis of colorectal cancer and a tumour that shows abnormal MLH1 expression by IHC, or microsatellite instability, who had BRAF V600E mutation testing.

Numerator – the number in the denominator who had BRAF V600E mutation testing.

Denominator – the number of adults with a new diagnosis of colorectal cancer and a tumour that shows abnormal MLH1 expression by IHC, or microsatellite instability.

Data source: The National Disease Registration Service collects data on performance of BRAF V600E mutation testing and results. The National Bowel Cancer Audit collects data on performance of BRAF V600E mutation tests.

c) Proportion of adults with a new diagnosis of colorectal cancer and a tumour that shows abnormal MLH1 expression by IHC, or microsatellite instability, and a negative BRAF V600E test who had MLH1 promoter hypermethylation testing.

Numerator – the number in the denominator who had MLH1 promoter hypermethylation testing.

Denominator – the number of adults with a new diagnosis of colorectal cancer and a tumour that shows abnormal MLH1 expression by IHC, or microsatellite instability, and a negative BRAF V600E test.

Data source: The National Disease Registration Service collects data on MLH1 promoter hypermethylation testing and results.

d) Proportion of adults with a new diagnosis of colorectal cancer and test results suggestive of Lynch syndrome-associated colorectal cancer who had genetic testing of germline DNA to confirm Lynch syndrome.

Numerator – the number in the denominator who had genetic testing of germline DNA to confirm Lynch syndrome.

Denominator – the number of adults with a new diagnosis of colorectal cancer and test results suggestive of Lynch syndrome-associated colorectal cancer.

Data source: The National Disease Registration Service collects data on the performance of germline testing for Lynch syndrome.

Outcome

Rate of diagnosis of Lynch syndrome in adults with a new diagnosis of colorectal cancer.

Data source: The National Disease Registration Service collects data on germline testing for Lynch syndrome.

What the quality statement means for different audiences

Service providers (such as histopathology laboratory services, molecular genetics laboratory services or genomic laboratory hubs) ensure that laboratory protocols are in place to provide testing for Lynch syndrome on tumours in adults with a new diagnosis of colorectal cancer. This includes IHC for mismatch repair proteins or microsatellite instability testing, BRAF V600E testing and MLH1 promoter hypermethylation testing. They include results in the standard pathology report requested by oncology. They ensure that laboratory protocols are in place to provide genetic testing of germline DNA for Lynch syndrome in adults with a new diagnosis of colorectal cancer and in whom test results are suggestive of Lynch syndrome.

Healthcare professionals (such as gastroenterologists, colorectal surgeons and consultant histopathologists) are aware of local protocols to ensure that adults with a new diagnosis of colorectal cancer have testing for Lynch syndrome. Healthcare professionals are aware of referral pathways and can identify when to refer to clinical genetics services for the diagnosis of Lynch syndrome.

Commissioners (clinical commissioning groups, integrated care systems or NHS England) ensure that they commission services that can provide tests for adults with a new diagnosis of colorectal cancer and genetic tests for those with results that suggest Lynch syndrome-associated cancer.

Adults with colorectal cancer have testing to check their tumour for changes that may mean they have Lynch syndrome. If changes are found, they will be offered further tests to be confirm whether or not they have Lynch syndrome. If they do, they can be monitored for other cancers and their close relatives can also be offered testing for Lynch syndrome.

Definitions of terms used in this quality statement

Testing for Lynch syndrome

Testing for Lynch syndrome in adults with colorectal cancer uses IHC to test for the expression of MLH1, MSH2, MSH6 and PMS2 proteins or PCR to test for microsatellite instability to identify tumours with deficient DNA mismatch repair. Results from these tests guide further sequential testing for Lynch syndrome. Further testing includes testing for BRAF V600E mutation, and if this is negative, testing for MLH1 promoter hypermethylation. Lynch syndrome can be confirmed by genetic testing of germline DNA. [Adapted from NICE's diagnostics guidance on molecular testing strategies for Lynch syndrome in people with colorectal cancer, recommendations 1.1 to 1.4 and expert opinion]

Test results suggestive of Lynch syndrome-associated colorectal cancer

Abnormal MLH1 expression by IHC or microsatellite instability, and negative tests for BRAF V600E and MLH1 promoter hypermethylation, or abnormal MSH2, MSH6 or PMS2 expression on IHC. [Adapted from NICE's diagnostics guidance on molecular testing strategies for Lynch syndrome in people with colorectal cancer, recommendations 1.2 and 1.3]