Family history of breast cancer and genetics

 

Breast cancer

Read answers to your questions about family history and genetics as part of our Breast Cancer Q&A with experts from Breakthrough Breast Cancer and Breast Cancer Care.

 

Letter Qsockapoodle: My family has a history of breast cancer, and I have a gene which makes me susceptible to breast cancer, BRCA1. But my daughter has not been tested. If she doesn't have the gene, is her risk the same as every other woman? Or would she still be at a higher risk due to my family history of breast cancer?

Letter ADr Caitlin Palframan, Policy Manager, Breakthrough Breast Cancer: If she doesn't have the gene, she would have the same risk as everyone else. The majority of genetic testing is a two-step procedure whereby a relative who has, or has had breast cancer must be tested first, before healthy relatives can be tested to see if they might also be at risk.

The first step of genetic testing is a diagnostic test where the genes of an affected relative (someone in the family who has or has had breast cancer) are tested first to find out if there is a fault running in the family.

Only if a fault in a gene is found through diagnostic testing can healthy relatives have predictive testing to see whether they have inherited this fault making them more likely to develop breast cancer. This is a personal choice that each family member makes for themselves.

Getting a negative (favourable) result from predictive genetic testing means that the mutation which has caused breast cancer in other members of the family has not been found and therefore the person being tested does not have an increased risk of developing breast cancer. They still have the same risk of developing breast cancer as the rest of the population.

 

Letter Q

sockapoodle: What is the situation for genetic selection IVF (that is the wrong term, I'm sure) as regards the BRCA genes? Is it available on the NHS? Has it become more popular?

Letter ADr Caitlin Palframan: A Prenatal Genetic Diagnosis (PGD) is a genetic test carried out as part of IVF where a known gene change is running in a family. This is tightly regulated in the UK. The embryos are tested for that particular gene change and those that do not have the change are implanted in the womb.

Whether to test embryos for susceptibility to diseases like breast cancer is a complex and personal issue which we've discussed at length with women with a family history of breast cancer. They tell us that what might be right for one woman may not be the best option for another, but it's important for parents to have access to information and support so they can make the right choice for them.

In order to be eligible for PGD, a potential parent must have had a positive genetic test for a BRCA1 or BRCA2 fault. If you are considering PGD, the Human Fertilisation and Embryology Authority recommends that you first talk to your GP about the options available. Your GP can also refer you to see a specialist at a hospital or fertility clinic. PGD may not always be available as an NHS treatment and each Primary Care Trust will decide individually whether or not funding can be provided. You should contact your local Patient Advice and Liaison Service to discuss your situation.

 

Letter Q10poundstogo: My mum and two of my aunts have had breast cancer. Later, one aunt then went on to develop ovarian cancer and died. My mum has had gene testing, and it said that nothing was found, but apparently they cannot rule it out - they just did not find it. Would it be worth getting my own risk checked? My Dad has also gone on to get kidney cancer so the pair of them have been in treatment, so it's been on my mind a bit about how much risk I've inherited – and passed on to my children.

Letter ADr Caitlin Palframan: A person is said to have a family history of breast cancer if they have an unusually high number of close relatives with cancer, often at a younger age then would normally be expected. If you are worried about your breast cancer risk you should visit your GP in the first instance and discuss your family history.

As you are aware, the results of some genetic tests are inconclusive. Diagnostic tests may not find an inherited fault in the genes currently known to increase the risk of developing breast cancer. This happens because, unfortunately, we don't yet know about all the genes responsible for increased breast cancer risk in families.

Your mother's inconclusive test result means that a mutation (fault) associated with an increased risk of developing breast cancer has not been found. The genetic cause of your breast cancer is still not understood and the results are inconclusive for your family. This does not mean that your family's risk of breast cancer is reduced. Any relative with a strong family history of breast cancer still has a greater chance of developing breast cancer than the general population.

 

Letter QRageagainstheteen: Both my aunts from my paternal and maternal side have suffered from breast cancer. My paternal aunt had a double mastectomy and is now in remission in her late 50s. My maternal aunt has inflammatory breast cancer, and sadly has terminal secondaries. She is in her late 30s. Am I at a great risk of either type of breast cancer? Should I be screened earlier than normal? I am in my 30s.

Letter QDinahrod: Can you be tested for BRCA 1 and BRCA 2 tested without having any surviving female relatives?

Letter QDinahrod: My mother had aggressive breast cancer at 45, pre-menopause, in both breasts and died aged 52; and my great-grandmother and my maternal aunt also had breast cancer but post-menopause. If you have a history of breast cancer in your family like mine, is it possible or advisable to request a preventative subcutaneous (nipple sparing) mastectomy?

Ought to add, I've had my breast-cancer genetic tree done two years ago and qualify for early mammograms starting at 40, but my mother had yearly mammograms in her 40s due to dense breasts/cysts, and sadly that did not prevent her dying from the disease.

Letter QBanana87: Both grandmothers (maternal and paternal) had breast cancer, and my maternal aunt. Does this make me higher risk? And at what age should I start having mammograms given this potential pre-disposition?

Letter QPinkbasket: My father's mother had breast cancer, had the breast removed and died six years later when cancer came back and was in several places. Am I at risk? Both my grandfathers died of lung cancer.

Letter QPandaEis: My mum, maternal grandmother and great-grandmother all had breast cancer in their 30s. At the time, me and my sister were told we would need yearly mammograms, starting 10 years before the age my mum was diagnosed (which was 38.) I'm now 28, and I spoke to my GP at my last appointment, but he said that despite my mum having aggressive fast-forming breast cancer that I wouldn't need to be referred for preventative screening because of my age. Is it still process for the preventative screening to be done? Or is it all based on post-menopausal women and I would have to have a lump to be checked?

Letter QMissAnnThrope: My mother died in her 50s of ovarian cancer, but as far as I know there isn't a family history of breast cancer. I know there is a connection between the two, but I'm not sure what it is. How do I find out, on the NHS, whether my mother's ovarian cancer makes me more likely to develop breast cancer? My own GPs seem to fudge the answer every time.

Letter QCustardismyhamster: My paternal aunt died recently due to breast cancer, and my paternal grandma and grandad both died of cancer (although not breast.) Am I at higher risk due to family history, or the same as anyone else?

Letter QSparklingby: I have been diagnosed with BRCA 1, having had breast cancer in one breast in 2000 and in the other in 2003. I would like to know what extra tests I am entitled to, other than the yearly check up, which includes a mammogram and breast examination.

Letter Qsmee: My friend had screening from the age of 40, because her aunt died of breast cancer. Does screening depend on where you live?

Letter Qcarriemumsnet: I wanted to know who was eligible for BRCA gene screening and for whom would it be useful? My mum died of breast cancer at the age of 50 after being diagnosed at 48. About 15 years ago we were told we couldn't be tested, but could we now and would it be useful? If I found I had gene I would definitely take action.

Letter QMumsie87: I have recently found out my paternal grandmother has had breast cancer for three years. She has been treated for it, but when I found out, I was worried for me and my sister. Is there a chance I could be at risk due to family history?

Letter ABreast Cancer Care nursing team: Thank you for your posts relating to a family history of breast cancer and genetic testing. Many of you raise interesting points and we have divided the information into three sections to try to address all of your questions.

1. Concerned about the risk of breast cancer because of a family history
2. Do I need earlier or extra screening because of my family history? 
3. Who can have a test to see if they have an inherited faulty gene? 
 

1. Concerned about the risk of breast cancer because of a family history

Many of you have family members who have been diagnosed with breast cancer. It can often be difficult seeing this and/or supporting family members through their diagnosis and treatments. Understandably, it may also lead you to wonder about your own risk of developing breast cancer.

As one in nine women will be diagnosed with breast cancer in their lifetime, it is not uncommon for more than one person to be affected within the same family. In fact, around 90% of breast cancers happen randomly, not as a result of being inherited. This means that only 5-10% are hereditary or familial (running in the family).

However, a family history is considered significant, when there are on the same side of the family (your mother's and father's side of the family are looked at separately):

  • Two or more close relatives (for example a mother, sister or daughter) who have had breast cancer
  • One or more close relatives who have had breast cancer before the age of 40
  • Close relatives who have had breast cancer and others who have had ovarian cancer
  • One close relative who has had breast cancer in both breasts (bilateral) or who's had breast and ovarian cancer
  • A male relative who's had breast cancer
  • An ethnic background where faulty breast cancer genes are more common - for example, people with Ashkenazi Jewish ancestry

If any of you are concerned about your own risk and would like to find out more, the first step is to see your GP who may take a detailed family history or refer you to a family history clinic. Try to find out as much about your family history as you can from other relatives before your appointment. It is especially important to know about your parents and siblings, as 50% of your genes come from your mum and 50% from your dad. Your GP or the family history clinic will refer you on to a more specialist genetics clinic if appropriate.

Some of your posts mention family members with other cancers, such as lung cancer and kidney cancer. Cancer (all types of cancer not just breast) affects one in three people. An individual's risk of developing cancer depends on many factors such as smoking habits and alcohol intake. In most cases, having family members with cancer elsewhere in the body does not alter the risk of hereditary breast cancer, but there are some exceptions (such as ovarian cancer), which is why you will be asked about all types of cancer in your different family members.

Breast Cancer Care has produced a booklet called Breast cancer in families, which explains about this in more detail. In addition, if someone is referred on to a specialised clinic, there is information about how the level of risk is assessed and what may then be recommended.


2. Do I need earlier or extra screening because of my family history?

All women have some risk of developing breast cancer, which is called the average or population risk. However, an assessment at a family history or specialist genetics clinic may result in you being considered at moderate or high risk of developing breast cancer.

Moderate risk is sometimes called raised risk because your risk is higher than average but it's still more likely that you won't get breast cancer as a result of having a family history. High risk means you are more likely than other women to develop breast cancer at some point in time, but it doesn't mean you will definitely get breast cancer.

Breast screening recommendations are based on national guidelines and the type of screening that you will be offered depends on your age and what risk category you are considered to be in. For example, someone at moderate risk of developing breast cancer may be offered regular mammograms between the ages of 40 and 49 before being invited to attend for routine breast screening every three years between the ages of 50 and 70 (changing to 47 to 73 over the next few years). Someone at high risk may be offered mammograms starting earlier than 40 and/or Magnetic Resonance Imaging (MRI).

Mammograms are not used for routine screening in women under 35 years of age because younger breast tissue is more dense and so it is much harder to get accurate results.

In 2004, the National Institute for Health and Clinical Excellence published guidelines relating to assessing a family history of breast cancer. Prior to this, specialists made more general recommendations about screening (for example, starting mammograms 10 years earlier than the age your family member was diagnosed at) based on their local hospital protocols.

NICE has produced a booklet for women with breast cancer in the family explaining the guideline. This may help you understand more about inherited breast cancer, how your risk will be assessed and also gene testing. 
 

3. Who can have a test to see if they have inherited a faulty gene?

If you are considered at high risk of developing breast cancer, genetic testing may be an option for you and other family members. Genetic testing is only available through a genetics department and following genetic counselling (which may take place over several appointments).

The first stage of testing involves taking blood from someone in your family who has been diagnosed with breast or ovarian cancer and checking this for one of the known faulty genes. If there is no one in your family who has had breast cancer and is still alive, it may, on rare occasions, be possible to have a genetics test. Your genetic counsellor will be able to advise you on the options.

The results from a genetics test can take several months. It can be hard to find a faulty gene, so sometimes a genetic test is inconclusive as 10poundstogo mentioned in her post. This means that it's possible for there to be a faulty gene somewhere, even though it hasn't been found.

If a faulty gene is found in the person with breast cancer, it means that a quicker genetic test is available for other relatives to see whether or not they also carry the faulty gene. If you are one of the people who posted to say they have inherited a faulty gene, it's important to remember that you won't necessarily go on to develop breast cancer. However, you do have a higher risk of developing the disease than people without a faulty gene.

Some of you, such as DinahRod, mention preventative surgery. Only women found to be at high risk or to have inherited a faulty gene would be offered what we now call risk-reducing surgery. This involves removing both breasts (bilateral or 'double' mastectomy) and although it significantly reduces the chance of developing breast cancer, it's important to realise that it cannot remove the risk completely. 


Being diagnosed with a BRCA gene or having a strong family history of breast cancer can often raise many issues. Breast Cancer Care has many ways in which to support people with breast health or breast cancer concerns. Some of you may be interested to know about our discussion forums and many people post specifically in our family history and genetics forum to exchange information and get support.
 

 

Disclaimer
We have made every effort to ensure that the content of these answers is accurate and up to date, but we accept no liability in relation to typographical errors or third-party information. Please be aware that the responses from the Breast Cancer Care and Breakthrough Breast Cancer teams are not a substitute for professional medical care. If you have any concerns about your breast health or any treatment you are receiving you should discuss these with your doctor. Responses from Breast Cancer Care and Breakthrough Breast Cancer are only accurate at the time of posting as medical knowledge and treatment can change over time.

Last updated: 11-Oct-2010 at 4:10 PM