HER2 positive breast cancer
HER2 (human epidermal growth factor) is a protein that can affect the growth of some cancer cells. It is found on the surface of normal breast cells. Some breast cancer cells have a very high number of HER2 receptors. The extra HER2 receptors stimulate the cancer cells to divide and grow. This is called HER2 positive breast cancer.
This information should ideally be read with our general information about primary breast cancer or secondary breast cancer, or our information for men with breast cancer.
What is HER2 positive breast cancer?
Back to top
The higher the level of HER2, the more likely the cell is to grow and divide. Between 15 and 25 out of every 100 women with breast cancer (15-25%) have HER2 positive cancers. Fewer men with breast cancer are thought to have HER2 positive cancers.
HER2 positive breast cancers tend to grow more quickly than HER2 negative breast cancers. However, effective treatments called targeted (or sometimes biological) therapies have been developed to treat HER2 positive breast cancer. The drug most commonly used is trastuzumab (Herceptin®).
All women diagnosed with breast cancer have a test done to check the HER2 level of the breast cancer cells. If you are a man with breast cancer you may want to discuss this with your cancer specialist.
Testing is usually done after you have had a sample of breast tissue removed (biopsy) when you are first diagnosed. Knowing if the cancer is HER2 positive or negative helps your doctors decide which treatments will be most effective for you.
If breast cancer comes back after initial treatment, women may have HER2 levels checked again. In a small number of cases (1 in 5 or fewer) the HER2 level may have changed. This can be checked by taking another biopsy. Your specialist will advise you if this is appropriate in your situation.
The two main methods used for HER2 testing are immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH).
IHC shows how much HER2 protein is present in the sample of tissue taken from the cancer. The HER2 level is graded from 0 to 3+.
0–1+ means there is a normal amount of HER2, and the result is HER2 negative
2+ means there is a moderate amount of HER2
3+ means there is a higher than normal level of HER2, and the result is HER2 positive.
If the result is 2+, guidelines recommend you have a FISH test (see below). The results of this test will help to identify people with a level of 2+ who will benefit from treatment with Herceptin.
FISH (fluorescence in-situ hybridization)
FISH measures the amount of a gene called the HER2/neu gene, which is responsible for the overproduction of HER2 protein in each cell. About 1 in 4 people (25%) with a 2+ result will have a positive FISH result.
The result will be either:
FISH negative, which means there are normal levels of the gene present
FISH positive, which means there is at least twice as much as the normal level of the gene present (the cancer is HER2 positive).
Your breast cancer specialist or breast care nurse will discuss your results with you.
Treatment for HER2 positive breast cancer
Back to top
HER2 positive breast cancer is treated in a similar way to other breast cancers. However, newer treatments called targeted therapies, such as Herceptin, have been developed specifically to treat it. Herceptin is only used to treat HER2 positive breast cancer.
Surgery to remove the cancer is usually the first treatment for primary breast cancer. But you may also have other treatments, as well as Herceptin, to reduce the risk of the cancer coming back. These include radiotherapy, chemotherapy and hormonal therapy.
Your specialist looks at different factors to assess which treatments are the most effective for you. These include:
the stage of the cancer (its size and whether it has spread outside the breast)
the grade of the cancer (how fast growing the cells are)
if the cancer cells are HER2 positive
if the cancer cells have receptors for the hormone oestrogen (which means they will respond to hormonal therapy).
If you have HER2 positive breast cancer that has spread to other parts of the body (secondary breast cancer), your treatment will depend on any previous treatment you have had and how long ago this was.
If you’ve already had Herceptin, or if the cancer has come back while you’re still having it, it can sometimes be used again or continued. Herceptin is usually given with chemotherapy but it can be given on its own or with hormonal therapy.
Sometimes a drug called lapatinib (Tyverb®) is used instead, which is a type of targeted therapy drug like Herceptin. It is given as a tablet and you may have it in combination with a chemotherapy drug called capecitabine (Xeloda®).
The type of surgery you have will depend on the size and position of the cancer. You and your doctor will decide which operation is best for your individual situation.
Wide local excision (lumpectomy)
This is the removal of a breast lump, together with some surrounding tissue. This is known as breast-conserving therapy. It removes the least amount of breast tissue, but leaves a small scar and sometimes a small dent in the breast. A wide local excision is usually followed by radiotherapy to the remaining breast tissue. For most women, the appearance of their breast is good after this type of surgery.
Removing the breast (mastectomy)
Sometimes your surgeon may advise you to have a mastectomy, or some women may choose to have a mastectomy. A mastectomy may be advised if the lump is large in proportion to the rest of the breast, or if there are areas of cancer in different parts of the breast.
Checking the lymph nodes
The surgeon will usually remove some or all of the lymph nodes in your armpit to check if any cancer cells have spread from the breast.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. Chemotherapy is usually given after surgery to reduce the risk of the cancer coming back (adjuvant treatment). Sometimes it is given in combination with Herceptin. Occasionally, chemotherapy and Herceptin are given before an operation (called neo-adjuvant treatment).
Women with HER2 positive breast cancer are usually treated with chemotherapy drugs known as either anthracylines or taxanes. Some studies show that these drugs work better than others for people with HER2+ breast cancer. You’ll usually have a combination of two or three chemotherapy drugs.
Chemotherapy can cause side effects including increased risk of infection, feeling sick (nausea) and tiredness. Many of the side effects can be reduced, so it’s important to tell your cancer doctor or nurse if you have any problems.
Anthracycline chemotherapy drugs aren’t given at the same time as Herceptin because they can both affect the heart. Your doctor or specialist nurse can give you more information about this.
Radiotherapy treats cancer by using high-energy rays to destroy the cancer cells. It is given after breast-conserving surgery and sometimes after a mastectomy to reduce the risk of the cancer coming back in that area. It can also be used to relieve pain caused by a cancer that has spread to other parts of the body, such as the bones.
Herceptin is one of a group of cancer drugs called monoclonal antibodies. Monoclonal antibodies are sometimes called targeted therapies because they work by ‘targeting’ specific proteins (receptors) on the surface of cells. Herceptin locks onto the HER 2 protein. This blocks the receptor and stops the cells from dividing and growing.
Herceptin is usually given following surgery and chemotherapy for primary breast cancer to reduce the risk of the cancer coming back. Even if you have a very small cancer that has not spread to the lymph nodes, your specialist may want to discuss the possible benefits of taking Herceptin in your situation.
Some women have Herceptin in combination with a course of chemotherapy. If you're having an anthracycline chemotherapy drug, Herceptin is usually started when chemotherapy has finished. If you’re being treated with taxane chemotherapy, Herceptin can usually be started at the same time. Occasionally, Herceptin is given with chemotherapy before surgery and then continued after surgery.
Because Herceptin can affect the way the heart works, you will have tests to check the health of your heart first. Some people with a history of heart disease or uncontrolled high blood pressure may not be able to have Herceptin.
Herceptin is usually given once every three weeks for a year. You will have it as a drip (infusion) into a vein in your hand or arm. Side effects tend to be mild and include flu-like symptoms, diarrhoea and headaches.
Lapatinib is another targeted therapy drug that works in a slightly different way to Herceptin, but is also effective in treating HER2 positive cancer. It’s a type of drug that interferes with the way cancer cells 'communicate' with each other, and can affect the cancer’s ability to develop.
Lapatinib is given in combination with the chemotherapy drug capecitabine (Xeloda®). It can also be given with hormonal drugs called aromatase inhibitors in women who have been through the menopause.
Lapatinib is a tablet that’s taken once a day. The side effects are usually mild and include diarrhoea, a rash and tiredness. Because it is a newer treatment, Lapatinib may not be widely available. Your specialist will explain if it's an option for you.
Breast cancers that have hormone receptors and need the hormone oestrogen to grow are known as oestrogen receptor positive (ER positive). Hormonal therapy blocks oestrogen from attaching to the cancer cells, or reduces the amount of oestrogen in the body. It’s often given after surgery to reduce the risk of the cancer coming back or to control the cancer if it has spread to other parts of the body (secondary breast cancer).
HER2 positive breast cancers tend to have less hormone receptors but some do respond to hormonal therapy. Drugs such as tamoxifen, anastrozole (Arimidex®), letrozole (Femara®) or exemestane (Aromasin®) can be used.
Research into treatments for HER2 positive breast cancer is ongoing. Cancer specialists use clinical trials to assess new treatments. Before any trial is allowed to take place, an ethics committee must have approved it and agreed that the trial is in the interest of the patients.
There are a lot of trials for women with HER2+ breast cancer, so you may be asked to take part in one. Your doctor will discuss the treatment with you so that you have a full understanding of the trial and what it involves. You may decide not to take part, or to withdraw from a trial at any stage. You will still receive the best standard treatment available.
This section has been compiled using information from a number of reliable sources, including:
National Institute for Health and Clinical Excellence (NICE). Early and localised breast cancer: Diagnosis and treatment. February 2009.
National Institute for Health and Clinical Excellence (NICE). Advanced breast cancer: Diagnosis and treatment. February 2009.
Kataja V, et al. Primary breast cancer: ESMO Clinical Recommendations for diagnosis, treatment and follow-up. Annals of Oncology. 2009. 20 (Supplement 4): iv10–iv14.
Harris JR, Lippman ME, Morrow M, Osborne CJ. Diseases of the Breast. 4th edition. 2010. Lippincott Williams and Wilkins.
Thank you to Professor Stephen Johnston, Professor of Breast Cancer Medicine, and all of the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.