Inherited cancers: breast and ovarian

Breast cancer is a common cancer. Most people who get it did not have a higher risk because of their family history. Even if you have two elderly relatives with breast cancer, this doesn’t mean you have an increased risk of developing it too.

However, 5-10% of breast cancers may be linked to genes. The genes most often associated with breast cancer are the BRCA1 and BRCA2 genes.

Talk to your doctor if you think your family history suggests you may be at increased risk of breast and ovarian cancers. Our online tool OPERA can help you assess your risk of developing these cancers. Your doctor may suggest you have genetic testing to establish your risk. They may recommend more frequent screening for breast and ovarian cancer if your risk is higher than normal. For women with very high risk of breast or ovarian cancer, there is the option of risk-reducing surgery.

Breast and ovarian cancer

Breast cancer is a common cancer – about 1 in 8 women in the UK will get it during their lifetime. If you have just one, or even two, elderly relatives diagnosed with breast cancer, it doesn't mean you are at a much increased risk yourself.

About 5-10% of all breast cancers are thought to be due to a strong hereditary susceptibility. This means that most breast cancers (9 in 10) happen without there being a strong family history of breast cancer.

The two genes most commonly involved in familial breast and ovarian cancer are the BRCA1 and BRCA2 genes (short for breast cancer 1 and breast cancer 2 genes). Although they are called breast cancer genes, they also affect the risk of ovarian cancer. A mutation in another gene, the TP53 gene, is also associated with an increased risk of breast cancer and some other types of cancers at a young age, but this is much rarer.

It's very likely that there are other genes involved in causing a susceptibility to breast cancer, but these haven't been identified yet.

If you’re worried about your family history of breast or ovarian cancer

You may want to see your GP, particularly if you have:

  • three close blood relatives from the same side of the family who developed breast cancer at any age
  • two close relatives from the same side of the family who developed breast cancer under 60
  • one close relative who developed breast cancer aged 40 or younger
  • a close male relative with breast cancer
  • a close relative with breast cancer in both breasts.

The GP will assess your family history and may refer you to a family cancer clinic or for genetic counselling.

Breast cancer is rare in men but does happen. It's possible to inherit a breast cancer susceptibility gene from your father's side of the family. In some families men with a faulty BRCA2 gene may be at increased risk of breast and prostate cancer.

Some cancer susceptibility genes cause an increased risk of both breast and ovarian cancer. You should also be referred to a specialist if you have:

  • at least one close relative who has had ovarian cancer and one close relative diagnosed with breast cancer when they were under 50 (this can also be in the same person).
  • two cases of ovarian cancer in close relatives.

If you’re worried that breast and/or ovarian cancer may run in your family, our online tool OPERA can give you personalised information about your risk, which you might want to take to your doctor to discuss.

OPERA is based on guidance on familial breast cancer from the National Institute for Health and Clinical Excellence (NICE). OPERA isn’t intended to replace professional genetic counselling services, so if you’re concerned about your genetic risk you should still consult your doctor.

Genetic testing

You won’t normally be offered genetic testing if you have only one close relative with breast cancer. But if a genetic counsellor or specialist thinks a susceptibility to breast or ovarian cancer may run in your family, they may offer you genetic testing.

If your family history suggests a high risk of breast cancer in your family, but you decide not to have the genetic test, you and all female blood relatives will usually be offered regular breast screening from the age of 40.

Assessing breast cancer risk

All women have some risk of developing breast cancer in their lifetime. But, most women don't get breast cancer, and even if you are told you have an increased risk, it doesn't mean you'll definitely get breast cancer.

If there is a history of breast cancer in your family, your doctor or genetics specialist will assess how this might affect your risk of developing breast cancer over your whole lifetime. They will also assess your risk of developing breast cancer by a certain age. Doing this will help them recommend the level of care - such as screening and risk-reducing treatments - that is most appropriate for you.

Women who have a significantly higher risk of developing breast cancer compared with women in the general population are classified into two groups:

  • women at raised risk
  • women at high risk (usually those who carry an inherited susceptibility gene).

Breast screening

Breast screening can't prevent breast cancer, but can help to detect it at an earlier stage. This increases the chances of successful treatment. Screening is usually done using breast x-rays (mammograms) and sometimes with MRI (magnetic resonance imaging) scans.

The type of screening you will be offered will depend on your estimated level of risk and your age.

At 50, all women in the UK, regardless of their personal risk, are offered regular breast screening. This is currently being extended to include all women aged 47 or over. If you're estimated to have a raised or high risk of breast cancer, you'll be offered breast screening with mammograms from the age of 40. NICE recommends that women at raised or high risk are offered yearly mammograms between the ages of 40 and 49.

In the UK, screening with mammograms has not been recommended for women younger than 40 because:

  • Mammograms are not as effective (the pictures aren’t as clear) in younger women, as their breast tissue is denser than that of older women.
  • There is a theoretical risk of the radiation doses (resulting from having many mammograms) causing cancer – for women over 40, doctors believe that this risk is outweighed by the benefit of detecting breast cancer earlier.

Another type of test sometimes used for screening women at high risk of breast cancer is an MRI scan. MRI scans use magnetism rather than radiation to detect changes in the breasts.

MRI scans aren't routinely used to screen women for breast cancer. However, NICE recommends the use of MRI breast screening in young women between 30 and 49 years who are at very high risk (for example, women who have one of the breast cancer susceptibility genes). MRI has been shown to be more sensitive tests than mammograms in this group of women.

Your consultant or genetic counsellor will be able to tell you if MRI screening is available in your area, and whether you meet the risk criteria to justify having these scans.

You might be very worried about your breast cancer risk, but find that you are not eligible for regular breast screening before the age of 50. Some women in this situation may consider paying for regular screening tests from private healthcare companies. But regular mammograms in the private sector may not be the right option for you, even if you’re very worried.

In this situation, it's best to speak to a breast care nurse or your genetic counsellor about why you are worried and the things you can do.

Ovarian screening

Some women with a higher than normal risk of ovarian cancer may be offered screening for ovarian cancer as part of a research trial. Screening may involve regular blood tests and ultrasound scans. An ultrasound is a painless test that uses sound waves to build up a picture of your ovaries.

NICE published guidance in 2011 to help improve ovarian cancer detection when women visit their GPs with possible symptoms.

Risk -reducing treatments

Some women at very high risk of developing breast or ovarian cancer are offered risk-reducing surgery.

There are two types of operation that may be done, depending on a woman's individual cancer risk:

  • risk-reducing breast surgery - This involves removing the breasts (mastectomy) – this is often followed by breast reconstruction
  • removing the ovaries and fallopian tubes (bilateral salpingo-ophorectomy) – this reduces the risk of ovarian cancer a great deal and may halve the risk of breast cancer if done before the menopause.

Although these operations greatly reduce the risk of cancer developing, they don't completely eliminate the risk. The decision whether or not to have risk-reducing surgery is not an easy one and will depend on many individual factors, including your age, your estimated risk of cancer, whether you still want to have children (for an operation to remove your ovaries) and your personal feelings.

If you are offered risk-reducing surgery it's very important to do what feels right for you and to take as much time as you need to make your decision.

Research trials

Research is looking into whether drugs, such as tamoxifen, can reduce the risk of breast cancer developing. You can discuss with your doctors the benefits and disadvantages of taking part in research trials.