Implementing Lynch Syndrome Testing and Surveillance Pathways

Overview

This specialist Guidelines summary covers key points from NHS England’s guidance to support local systems in the implementation of Lynch syndrome testing and surveillance. It sets out best practice and includes several useful algorithms.

By implementing Lynch syndrome pathways nationally, many colorectal and endometrial cancers may be detected earlier or prevented through surveillance and risk reduction treatments.

This summary is for secondary care oncology teams. For further information, refer to the full guideline.

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Implementing Lynch Syndrome Pathways

The Lynch syndrome pathway can be split into four stages, as shown in Box 1.

Initial Tumour Test

• NICE guidance recommends that:
  • all people with colorectal cancer should be tested for Lynch syndrome using one of two initial tumour tests: immunohistochemistry (IHC) or microsatellite instability (MSI)
  • all people with endometrial cancer should be tested for Lynch syndrome using IHC
• A biopsy should be sent directly from endoscopy/gynaecology to pathology for:
  • diagnosis of cancer and IHC testing, or
  • diagnosis of cancer and preparation, then sent to the relevant genomic laboratory hub (GLH) for MSI testing
• Patients may present by alternative routes, and consideration should still be made for Lynch syndrome testing    
• BRAF V600E testing is not used in the endometrial pathway
• Informed consent for germline testing is mandatory, but not for preceding steps in the diagnostic pathway; a decision can be taken locally on whether to take informed consent before the initial tumour test or before the germline test.

Testing for Lynch Syndrome Using Immunohistochemistry

• Integrated Care Boards (ICBs) are responsible for providing funding to pathology services for IHC testing
• See Algorithm 1
• The initial tumour test should be a part of standard pathology, and germline testing should be part of a mainstreaming approach
• IHC testing should be completed within 7–10 days.

Testing for Lynch Syndrome using Microsatellite Instability

• MSI is included in National Genomic Test Directory and is therefore funded nationally by specialised commissioning
• There will also need to be funding for histopathological assessment, the responsibility for this lies with ICBs
• See Algorithm 2
• Steps across this pathway and the time taken to complete the test may differ depending on the MSI assay used by the GLH
• MSI, BRAF, and hypermethylation testing should be completed before the multidisciplinary team meeting, and results communicated to the patient within 4 weeks.

Germline Testing Following Either Immunohistochemistry or Microsatellite Instability Testing

• Commissioners should support the provision of genetic testing by local cancer teams, clinically supported with regional multidisciplinary expertise including genetics and expert clinical networks
• See Algorithm 3
• Germline testing should be part of a mainstreaming approach
• If the germline test is negative but the patient has a significant family history of cancer or was diagnosed under age 30, consider referral to clinical genetics service
• A germline test should be completed, and results communicated to the patient within 4 weeks.

Algorithm 3: Germline Testing Following Either Immunohistochemistry or Microsatellite Instability Testing

Management of Index Case

• See Algorithm 4
• See guidance on the management of gynaecological cancers in Lynch syndrome from the Manchester International Consensus Group
• Public Health England is working with an expert advisory group to consider the appropriateness and feasibility of referring people with Lynch and Lynch-like syndrome for surveillance into the NHS Bowel Cancer Screening Programme. For now, patients with Lynch syndrome should receive colonoscopy at trust level by a screening accredited colonoscopist, in accordance with guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology.

Algorithm 4: Management of Index Case

Cascade Testing and Surveillance of Family Members

• ICBs are responsible for gynaecological surveillance
• NHS bowel cancer screening is responsible for endoscopic surveillance
• See Algorithm 5.

Algorithm 5: Cascade Testing and Surveillance of Family Members