The Scottish Clinical Genetics group includes healthcare professionals overseeing the clinical genetics service in Scotland who investigate, monitor and counsel patients with increased genetic risks for cancer. The Group has collaborated to draw up a framework for undertaking testing and risk assessment for breast cancer in Scotland.
Whilst the Clinical Management Pathway for breast cancer is directed towards treatment of those already diagnosed with breast cancer, we have included the guidance from the Genetics Group to advise on which breast cancer patients may be suitable for further genetic testing and planning of their care on this basis. What is not included here is advice for family members and others who may be at risk of breast cancer in the future but do not yet have a diagnosis. This group do require a system for keeping them under review and for screening. The Scottish Government is currently working with the Scottish Clinical Genetics Group to plan the service required for these high-risk people as a distinct programme.
Following a diagnosis of breast cancer, should you be considered for genetic testing?
You may be offered a gene panel test if you have been diagnosed with a cancer that meets one or more of the following criteria:
Breast cancer under age 40
Bilateral breast cancer (right and left breast), both under age 60
Triple negative breast cancer (TNBC), under age 60
Breast cancer under age 45 with (at least) one 1st degree relative under age 45
Breast cancer AND ovarian cancer, any age
Male breast cancer, any age
Breast cancer AND 10% or more probability of a germline pathogenic/likely pathogenic variant based on the commonly used risk assessment tools eg CanRisk
Testing will be requested to inform treatment and follow-up if you are suspected of having familial risk. This will usually be initiated by the breast surgical or oncology team, with referral to the clinical genetics service for counselling and support if a likely significant gene result is detected.
Referral to Clinical Genetics
If you are newly diagnosed with breast cancer and receive a genetic test result which suggests you have an increased cancer risk, then your relatives also at risk of inheriting this can be offered testing, regardless of whether they have had cancer or not. The Clinical Genetics team can offer predictive testing to at-risk relatives and provide individualised risk assessments, based on genetic test results combined with family history, to calculate the overall lifetime risk of cancer.
Categorising Risk
– A very high risk of breast cancer is defined by a more than 40% chance of developing the disease in a lifetime. This category defines people who have a gene specifically predisposing them to developing breast cancer (gene carrier). – High risk equates to a lifetime risk of 30% of developing breast cancer. – Moderate risk is between 17-30% lifetime risk of breast cancer. – Low risk is 17% or less, reflecting the normal background population risk.
Each of these categories is defined by the number of first- or second-degree relatives affected – further information here. The detail of these categories and their implications should be discussed in full with the Clinical Genetics Team who will explain what is relevant to you.
Implications of increased lifetime risk of breast cancer
If you have already been diagnosed with breast cancer or have been identified as increased lifetime risk based on genetic screening due to family history/affected relative, there are different options to consider as to what may be helpful for your care.
Screening
‘Enhanced’ screening (more tests than are normally done for the rest of the population) is recommended according to the level of risk. If you are deemed very high risk the recommendation will be to commence annual MRI (Magnetic Resonance Imaging) screening at the age of 25. MRI is preferred over mammography in young females before the menopause. The frequency and nature of screening varies with the risk category and should be overseen by the Clinical Genetics team in combination with the local breast clinic.
Risk reducing surgery
Risk reducing bilateral mastectomy (both breasts) is only appropriate if you are from a high-risk family and should be discussed in full with your multidisciplinary team. If you are considering risk reducing surgery because of an increased familial risk, you should have had your risk assessed by Clinical Genetics and have access to Clinical Psychology.
Females affected with breast cancer
Contralateral mastectomy (removal of the breast on the opposite side) is not generally advised for those with one sided cancer due to the risk of surgery being doubled with no evidence that this will improve your survival. However, where there is a lifetime risk of 30% or greater that you may develop cancer on the opposite side, removal of the other breast may sometimes be considered. This needs to be discussed and considered with the team looking after you.
Risk reducing removal of both ovaries
If you have a genetic variant or a family history that increases your risk of ovarian cancer by 5% or more, it may be reasonable to discuss the risks and benefits of surgical removal of both ovaries. This will reduce the risk of subsequent ovarian or breast cancer but does not eliminate the risk and it will cause you to go into the menopause after the surgery. This needs to be weighed up with appropriate counselling.
Insurance implications of positive genetic testing
In 2018 the Association of British Insurers agreed that individuals testing positive for a genetic variant which increases their risk of cancer do not have to disclose this in applying for life or critical illness insurance. Having a cancer diagnosis will impact insurance risk but for now having an increased risk of cancer does not.
