Dr Sarah Taylor, GatewayC GP Lead, speaks to Dr Fiona Lalloo, Consultant Clinical Geneticist, about cancer genetics.

Key points:

• • There are 2 types of genetic mutations:
    • Somatic mutations – these are mutations which are confined to the tumour and are useful to direct treatment 
    • Germline mutations – these are mutations which affect every cell in the body. This can affect treatment but can also cause a predisposition to malignancies for the patient and members of their family
  • Patients with germline mutations need referral to a genetics service. This is normally done by the oncology team, but primary care practitioners may be asked to refer family members
  • In that case it useful to know the name of the affected patient, the type of cancer and where they are being treated
  • Many cancers are environmental but 5-10% of cancers have a germline mutation
  • There are some cancer syndromes which have specific clusters of cancer types.

The National Genomic Test Directory lists the referral criteria for genetic testing for patients
who are concerned about a family history of cancer

Factors which increase the probability of a germline mutation are:

• cancers occurring at young age
• individuals with more than one primary
• clusters of cancer within a family

Many cancers are environmental, but 5-10% of cancers have a germline mutation.

There are some cancer syndromes which have specific clusters of cancer types.

Genomic testing in Wales

While the National Genomic Test Directory is owned, controlled and maintained by NHS England, the Welsh Health Specialised Services Committee (WHSSC) approve funding of genomic testing in line with the criteria identified in the Test Directory and implementation of these tests is being clinically prioritised in collaboration with a range of clinicians through the All Wales Medical Genomics Service.

Prostate Cancer

Risk Factors

Hereditary prostate cancer accounts for about 5-9% of newly diagnosed prostate cancer cases. There are a number of pathogenic germline mutations associated with increased risk of developing prostate cancer, including BRCA2, Lynch syndrome (MSH2, MSH6), ATM, and Li Fraumeni syndrome.

There is a greater risk of developing prostate cancer amongst Black males and Ashkenazi Jews. Studies suggest that a number of genetic mutations in Black men predispose them to this disease and that Ashkenazi Jews are more likely to carry the BRCA genes linked to increased risk.

Family history of prostate cancer and associated cancers such as breast, ovarian and pancreatic impact on risk. The risk increases in line with the number of first-degree relatives (FDR) that have been diagnosed with these cancers, particularly at a younger age of diagnosis.

Screening

Current guidelines from the UK National Screening Committee advise that there is no role for population screening for prostate cancer with PSA tests. While patients can request a PSA test, primary care professionals should discuss the pros and cons of screening with the patient.

National guidelines for high genetic risk groups are yet to be developed.

Additional resources

Link: National Genomic Test Directory, NHS England (2022)
Link: All Wales Medical Genomics Service