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Breast And Ovarian Cancer (BRCA 1 and 2)

THIS SECTION IS CURRENTLY BEING REVISED - THE UPDATED VERSION WILL BE AVAILABLE AUTUMN 2016.

General description of breast cancer

Breast cancer is a disease in which the breast cells grow and reproduce themselves abnormally. Excess cells form a mass called a tumour, which in cases of breast cancer, is cancerous or ‘malignant’. Malignant tumours spread to other sites in the body where they begin to grow and replace normal tissue, forming new tumours which can be life-threatening.

Breast cancer is very common in women and affects 1 in 9 women in the UK general population - all women have approximately an 11% chance of the developing the disease in their lifetime. Men can also be affected but this is rare. Breast cancer is largely diagnosed over the age of 50 years and the NHS National Breast Screening programme offers 3 yearly mammograms to all 47-73 year old women.

General description of ovarian cancer

Ovarian cancer is a disease caused by rapid growth and division of cells within one or both ovaries. The ovaries are the reproductive glands that make the ova (eggs) and the female sex hormones. Ovarian cancer is a general term that includes cancer of 30 different ovary-related tissue types. Though it can be life-threatening, disease prognosis varies greatly depending upon age of the individual, the cancer stage at time of diagnosis and also the cancer tissue type affected. Ovarian cancer affects 1 in 70 women in the UK occuring most frequently in women over 60 years of age, and does not affect men.

Familial breast / ovarian cancer and cancer susceptibility genes

The majority of cases of breast and ovarian cancer occur sporadically, that is, without any identifiable underlying genetic cause. However, in the general UK population, approximately 5-10% of breast and ovarian cancer cases are thought to be familial i.e. caused by an inherited susceptibility.

Familial cancers are caused by specific susceptibility or ‘predisposition’ genes that, when influenced by other genetic and environmental factors, increase an individuals risk of developing cancer relative to the general population. It is important to understand that having mutation in a cancer susceptibility gene does not mean that an individual will definitely develop cancer; they are simply at a higher risk of doing so.

Currently there are a number of known genes that, when they contain a mutation cause an increased susceptibility to breast, and also ovarian cancer. These genes include BRCA 1 and BRCA 2. Not all families with a strong history of breast/ovarian cancer have mutations in BRCA 1 or 2 as other genes can also cause susceptibility to these cancers.

Overview of BRCA 1 and BRCA 2 susceptibility genes (BRCA 1 and 2)

BRCA 1 and 2 are tumour suppressor genes, or genes which regulate cell growth and are necessary to stop cancer from developing. These genes are involved in repairing damage to DNA and have other functions that are not fully understood. When tumour suppressor genes no longer function due to mutations, cancer may develop. BRCA 1 and 2 are cancer susceptibility genes associated with breast and ovarian cancer.

BRCA 1 and 2 and inheritance

BRCA 1 and 2 genes are inherited in an autosomal dominant manner. A person who has a mutation in either of the BRCA 1 or 2 genes has a 50% chance of passing on that mutation to each of their children.

It is important to note that these genes, though dominant, have reduced penetrance. Someone that carries a BRCA 1 or 2 mutation is more likely, but not guaranteed, to develop cancer relative to someone in the general population.

Prevalence of BRCA 1 and 2 susceptibility genes

In the UK general population it is thought that no more than 1 in 500 people carry mutations in BRCA 1 or 2, and many hundreds of different mutations have been identified that are carried in different families.

Whilst the total incidence of breast and ovarian cancer may be somewhat higher in the Ashkenazi Jewish population than in the general population, the number of Ashkenazi Jewish people who carry BRCA 1 or 2 gene mutations is notably higher. Three specific mutations have been found that are thought to account for the majority of cases of familial breast cancer in the Ashkenazi Jewish population.

It is estimated that around 1 in 40 people of Ashkenazi Jewish ancestry carry one of these three mutations.

Cancer risks for carriers of a BRCA 1 or 2 mutation

For women who carry the BRCA 1 or 2 mutations, the risk of developing breast cancer by the age of 80 years will be increased to approximately 55%-70% from the estimated 11% risk in the general population.

The lifetime risk of developing ovarian cancer for BRCA 1 or 2 mutations carriers will be approximately 20%-33%, relative to 1%-2% risk in the general population. The level of risk will depend on the particular gene and mutation.

It is important to reiterate that carrying the BRCA 1 or 2 mutations increases the risk but does not guarantee that cancer will develop. 30%-45% of carriers never develop breast cancer and 67%-80% of carriers never develop ovarian cancer. It is not yet known why some carriers develop cancer and others do not. It is also worth remembering that the risk of developing cancer is not the same as the risk of dying from cancer – even if cancer develops, there is a good chance that the disease can be cured if detected and treated early.

Men are as equally likely to carry these mutations as women but the cancer risks for male carriers are very much less significant. In addition, BRCA 2 male carriers have a slightly increased risk of prostate cancer later in life.

Assessing the risk of carrying a BRCA 1 or 2 mutation

Certain people are more at risk of carrying a BRCA 1 or 2 mutations than others. Families where there are several close blood relatives (e.g. sister, mother, grandmother, aunt) affected with breast or ovarian cancers, and where the diagnoses of breast cancer occurred before the age of 50, are most at risk.

Depending on your family history your GP can refer you to either a local breast clinic, or your regional genetics service. Your family history will then be further assessed, and in certain cases it may be possible to offer additional mammograms for women at increased risk. In some families it is also possible to offer genetic testing for BRCA 1 and 2 mutations via your regional genetics service.

Diagnostic genetic testing for BRCA 1 and 2 mutations

If there is a significant family history of breast and/or ovarian cancer, and if one of the affected relatives is available for genetic testing, the first step is usually to take a blood sample from one of the affected relatives in order to do a ‘mutation search’ or diagnostic test. This test looks at both BRCA 1 and BRCA 2 to try and find a mutation that could have caused the cancer. In Ashkenazi Jewish families, this test may first look for the three common mutations that occur in this population.

Predictive genetic testing for BRCA 1 and 2 mutations

Predictive genetic testing can be carried out on a person who does not have cancer but has a strong family history of the disease. Where possible, this is offered after a mutation has already been identified in the family by diagnostic testing of an affected relative (as described above). If a mutation is found, predictive testing can then be done to examine the blood sample of an ‘at risk’ individual to see if they have the same mutation.

A predictive test in the presence of a known mutation in the family is relatively simple and highly accurate. However, testing without knowing the family mutation is more complex and far more difficult to interpret. 

Predictive testing may identify the presence of a mutation and help individuals to better understand their risks for developing cancer – it cannot, however, confirm whether or not cancer will develop. This type of testing has far reaching implications for an individual, and is performed only after genetic counselling, which is offered by regional genetics centres.

Where there is a strong family history of breast/ovarian cancer found to be associated with a BRCA 1 or 2 mutation, other relatives can be offered ‘predictive genetic testing’ to see if they also have the mutation.

Options available to BRCA 1 or 2 carriers for managing the risk of developing cancer

Screening:

BRCA 1 or 2 carriers can be monitored closely to detect cancer as early as possible by having regular mammograms and MRI. Currently, within the NHS it is recommended that BRCA 1 or 2 carriers are offered additional mammograms annually from age 40 – 49, after which 3 yearly screening is offered through the National Breast Screening programme. More frequent mammograms may be offered after the age of 50, but this may vary locally. In addition, annual MRI screening has been recommended from age 30 – 49, although NHS funding for MRI screening may vary locally.

Ovarian screening methods are currently being researched and it has been suggested that annual pelvic ultrasound scans and regular CA125 blood tests could be beneficial. However further evidence of the effectiveness of this screening is awaited.

Risk reducing surgery:

Some women who carry BRCA1 or 2 mutations decide to have their breast tissue removed (mastectomies) before cancer occurs in order to reduce the chance of it developing. Depending on the type of surgery, this can reduce the risk by 90% or more but cannot remove the risk completely. Many women may also have reconstructive surgery at the same time for a better cosmetic result.

Risk reducing surgery can also involve removal of the ovaries and fallopian tubes to reduce the chance of getting ovarian cancer. This surgery causes early menopause and is not usually performed before the age of 40, and when a woman has completed her family. However this surgery also has the benefit of reducing the risk of breast cancer as well, if the breast tissue has not been removed.

The decision to have risk reducing surgery can be a complex one. It is important to fully discuss the pros and cons of the different options with a genetic counsellor, breast surgeon, gynaecologist and psychologist.

Breast and Ovarian cancer treatment and prognosis

Breast and ovarian cancers are life-threatening diseases, however, a range of treatments are available that can remove the cancer and potentially stop disease progression. The type of treatment chosen and how effective it may be varies among individuals. Anyone diagnosed with these cancers is advised to speak with their specialist to understand more about their personal situation and treatment options.

Please click on the titles to open and close the following information section.

Macmillan Cancer Support (merged with Cancerbackup)

Macmillan provides care and support for people with cancer at every stage of their illness by offering medical help, information, advice and emotional support to cancer patients and their families, and financial help and advice for patients in need. Their website, specialist cancer nurse helpline, and high-quality publications are available free to everyone who needs them.

Macmillan CancerLine: 0808 808 0000 (Mon to Fri, 9am to 9pm)
Email: .(JavaScript must be enabled to view this email address)

Cancer Research UK

Cancer Research UK, the largest cancer research organisation in the UK, are involved in the development of new anti-cancer drugs, funding research, producing high quality information for people affected by cancer, health professionals and the general public. Their services include a website, leaflets, specialist cancer nurse helpline, and cancer chat forum.

General inquiries: 020 7242 0200 Helpline: 020 7061 8355 or freephone 0808 800 40 40

Breast Cancer Now

Dedicated to improving early diagnosis, developing new treatments and preventing all types of breast cancers. The website provides general information about breast cancer which includes a downloadable guide for people with a family history of breast cancer

Breast Cancer Care

Dedicated to providing support and information to women with breast cancer or other breast-related problems as well as to their families, partners and friends.

Helpline: 0808 800 6000
Email: .(JavaScript must be enabled to view this email address)

BRCA Umbrella

This moderated internet group offers access to a range of highly practical and supportive discussion forums covering issues faced by individuals affected by or at risk of having a BRCA mutation. 

Chai Lifeline / Chai Cancer Care

Chai is the Jewish community’s cancer support organisation that provides many services including counselling, therapies, complementary therapies, helpline, social and physical activities, advocacy and advice and expert lectures. Services are available to patients, families and friends from their Hendon base, Redbridge, South London, and Greater Manchester.

Freephone Helpline: 0808 808 4567 Tel. 020 8202 2211 Fax: 020 8202 2111
Email: .(JavaScript must be enabled to view this email address)

Breast Cancer Haven

With centres in London, Hereford and Leeds, Haven offers free support - including counselling, complementary therapies, stress reduction, support groups and nutritional advice - to help anyone with breast cancer cope with the physical and emotional symptoms of cancer and its medical treatment. Online and telephone support is also available.

Helpline: 08707 272 273 Tel: 020 7384 0000 Fax: 020 7384 0001
Email: .(JavaScript must be enabled to view this email address)

NHS Breast Cancer Screening Programme

This website provides a variety of information resources in different formats designed to help answer questions regarding all aspects of the NHS breast screening programme. This screening programme is targeted at people without symptoms of breast cancer.

Ovacome

A support organisation for people effected by ovarian cancer. It develops and works with other cancer organisations to provide relevant literature.

Support service: 0845 371 0554
Email: .(JavaScript must be enabled to view this email address)

The National Hereditary Breast Cancer Helpline

This charity provides help and information for people concerned about hereditary breast cancer. It has a range of support forums including one for the Jewish community. The website includes personal stories, factsheets, and an on-line forum.

24 hour helpline: 01629 813 000

To find out more about general resources relevant to Jewish genetic disorders, please visit our resources and support section.

Written by Jnetics.
Approved by Professor Ros Eeles, Professor of Oncogenetics at the Institute of Cancer Research, Royal Marsden Hospital
Last review: 10.01.2010