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Macmillan and Cancerbackup merged in 2008. Together we provide free, high quality information for people affected by cancer through our publications, website and phone service. Find out more|.
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This information is about HER2 positive breast cancer|. HER2 is a protein that can affect the growth of some cancer cells.
To understand HER2 positive breast cancer, it helps to understand a bit about receptors and growth factors.
HER2 is a protein found on the surface of normal breast cells. It’s a growth factor receptor and helps normal cells grow and divide.
Some breast cancer cells have an abnormally high number of HER2 receptors. These cancers are described as being HER2 positive (HER2+). The more HER2 there is on the surface of the cell the more likely it is that the cell will be stimulated to grow and divide.
Between 15 and 25 out of every 100 women with breast cancer (15-25%) have HER2+ cancers. Fewer men with breast cancer are thought to have HER2+ tumours.
HER2+ breast cancers tend to grow more quickly than HER2 negative (HER-) breast cancers. However, effective treatments called biological| or targeted therapies have been developed to treat HER2+ breast cancer. The drug most commonly used is trastuzumab (Herceptin®).|
Since 2006, everyone who's diagnosed with breast cancer in the UK will have tests to measure the level of HER2. Anyone who was treated for breast cancer before 2006 will be tested if needed, for example if the cancer comes back. Knowing if a cancer is HER2 positive or negative helps your doctors decide which treatments will be most effective for you.
A sample of cancer cells is usually tested when you're first diagnosed| with breast cancer. Samples of tissue from previous biopsies or surgery may also be used.
If breast cancer comes back after initial treatment, tests may be done to check the HER2 status again. This is because for a small number of breast cancers (1 in 5 or fewer) the HER2 status may change. A breast cancer that was initially HER2+ may become HER2- when it recurs, and a HER2- breast cancer that comes back may become HER2+. 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).
Immunohistochemistry (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+.
When a result is scored at 2+, UK testing guidelines recommend that further testing is done using a FISH test (see below). This is because some people with a level of 2+ will benefit from treatments specifically aimed at HER2+ breast cancer, and the FISH test can help identify these people. About 1 in 4 people (25%) with a 2+ result will have a positive FISH result.
IHC only measures the level of HER2 protein in the tissue sample but FISH measures the amount of a gene called the HER2/neu gene. This gene is responsible for the overproduction of HER2 protein in each cell.
The result will be either:
A FISH-positive result means that the breast cancer is HER2 positive (HER2+).
Your breast cancer specialist or breast care nurse will discuss your HER2 results with you.
The treatment for breast cancer is individual for each person, and your doctor will talk to you about all the options available to you.
There are many factors that your doctor will consider when deciding which treatment to recommend for you. These include:
Primary breast cancers are often treated with surgery to remove the tumour. You may also have other treatments, such as chemotherapy, radiotherapy, targeted therapy and hormonal therapy.
The treatment of secondary breast cancer| depends on which parts of the body the cancer has spread to. Treatment can include chemotherapy, radiotherapy, targeted therapies, hormonal therapy and treatments to control symptoms.
HER2+ breast cancer is treated in a similar way to HER2– breast cancer. However, newer treatments called targeted therapies have been developed specifically for HER2+ cancers. The most common targeted therapy used for HER2+ breast cancer is trastuzumab (Herceptin®). You may be given these newer treatments on their own or in combination with chemotherapy| or hormonal therapy| depending on your situation.
Surgery| is usually the first treatment for early breast cancer. Chemotherapy is often given after surgery (known as adjuvant treatment), followed by Herceptin. Sometimes chemotherapy and Herceptin are given in combination rather than one after the other. Occasionally, chemotherapy and Herceptin are given before an operation (called neo-adjuvant treatment), and Herceptin is then continued on its own after surgery.
If the cancer is smaller than 1cm and it hasn’t spread to the lymph nodes, you may not need Herceptin. If you’ve only had part of the breast removed, radiotherapy is usually given to the remaining breast tissue. The cancer will also be tested to see how it reacts with the hormone oestrogen. If it's responsive to oestrogen, hormonal therapy will also be given.
The treatment of secondary (metastatic) HER2+ breast cancer will depend on which treatments, if any, you’ve already had and how long ago. If you have chemotherapy, it will probably be with different drugs to any you’ve had before. If you’ve already had Herceptin, or if the cancer has come back while you’re still being treated with Herceptin, it can sometimes be used again or continued. However, sometimes another targeted therapy called lapatinib (Tyverb®)| is used instead.
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.
This is the removal of a breast lump, together with some surrounding tissue. A wide local excision is usually followed by radiotherapy to the remaining breast 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. For most women, the appearance of their breast is good after this type of surgery.
Sometimes your surgeon may advise you to have a mastectomy|. This is when the surgeon removes the whole of your breast. There are different reasons for doing this. For example, it may be needed if the lump is large in proportion to the size of the breast. It may also be needed if there are several areas of cancer in different parts of the breast or a lump just behind the nipple.
Your surgeon will explain why they think it’s the best treatment for you.
As part of any operation for breast cancer, the surgeon will usually remove one or more of the lymph nodes from under your arm on the same side as the cancer. The nodes will be examined to see if any cancer cells have spread into them from the breast.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. If you have HER2+ breast cancer, you’re likely to be treated using chemotherapy drugs known as either anthracylines or taxanes. Research| has shown that these chemotherapy drugs work better than others for people with HER2+ breast cancer. Often a combination of two or three chemotherapy drugs is used.
The main anthracycline drugs used are:
The taxanes used are:
Chemotherapy can cause side effects such as being more at risk of getting an infection|, feeling sick (nausea) and vomiting| and tiredness|. Many side effects can be relieved or reduced, so it’s important to tell your doctor or nurse if you have any problems. Anthracycline chemotherapy drugs can cause damage to the heart so they aren’t usually given at the same time as Herceptin, which can also affect the way the heart works. Your doctor can give you more information about this.
Radiotherapy treats cancer by using high-energy rays to destroy the cancer cells, while doing as little harm as possible to normal cells. It may be used to reduce the chance of the cancer returning after surgery.
Radiotherapy may also be used to relieve pain or discomfort caused by a cancer that has spread to other parts of the body, such as the bone.
Many breast cancers have hormone receptors and need the hormone oestrogen to grow. They are known as ER positive (ER+) breast cancers.
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.
HER2+ breast cancers tend to have less hormone receptors, but some do respond to hormonal therapies. Drugs such as tamoxifen| anastrozole (Arimidex®),| letrozole (Femara®)| or exemestane (Aromasin®)| can be used to treat HER2+ breast cancers that are ER positive.
Hormonal therapy may also be used to control the cancer if it comes back (secondary breast cancer).
Herceptin is one of a group of drugs called targeted therapies. It's a type of drug known as a monoclonal antibody|
It attaches itself to the HER2 protein on the cell surface and blocks it from connecting with the growth factor. This can help to slow down or stop the cancer cells from dividing. Herceptin only works when the cancer has high levels of the HER2 protein (HER2+). It isn't used to treat HER2 negative breast cancer.
When it's used to treat primary breast cancer, Herceptin is given once every three weeks for a year. It can be given in combination with a course of chemotherapy after an operation to remove the cancer (adjuvant treatment) or sometimes before surgery (neo-adjuvant treatment).
If you're being treated with an anthracycline chemotherapy drug, Herceptin is usually started once the course of chemotherapy has finished. If you’re being treated with taxane chemotherapy, the Herceptin can be started at the same time.
The use of Herceptin after surgery and chemotherapy has been recommended by the National Institute for Health and Clinical Excellence (NICE)| – the government body that currently advises doctors about which treatments to use.
Herceptin may also be used to treat secondary (metastatic) breast cancer. It’s most often used in combination with chemotherapy but is sometimes given on its own or with hormonal therapy. NICE recommends its use in some circumstances, and your doctor or breast care nurse can talk to you about whether it's suitable for you.
Herceptin is given as a drip (infusion) into a fine tube (cannula) inserted into a vein in your hand or arm. Side effects tend to be mild and include flu-like symptoms, diarrhoea| and headaches. It can affect the way the heart works, so you may not be given it if you have a history of heart disease or high blood pressure. Before being given Herceptin, you'll have tests to check the health of your heart.
Lapatinib is another targeted therapy that works in a slightly different way to Herceptin. It’s also effective in treating cancers that are HER2+. It’s a type of drug known as a growth inhibitor|. Growth inhibitors interfere with the way that cancer cells 'communicate' with each other and can affect the cancer’s ability to develop.
Lapitinib is used to treat advanced, secondary breast cancers that are HER2+. It's given in combination with the chemotherapy drug capecitabine (Xeloda®)|. It's also given with hormonal therapy drugs, such as anastrozole (Arimidex®),| letrozole (Femara®)| or exemestane (Aromasin®),| which are given to post-menopausal women.
Lapatinib is a tablet that’s taken once a day. The side effects of lapatinib are usually mild and include diarrhoea, a rash and tiredness|. Lapatinib is a newer treatment, so it may not be widely available. Your specialist will explain if it's an option for you.
Research| into treatments for HER2+ breast cancer is ongoing, and advances are constantly being made. Cancer doctors use clinical trials to assess new treatments. Before any trial is allowed to take place, an ethics committee must approve it and agree that it's in the interests of patients.
There are a lot of trials for women with HER2+ breast cancer so you may be asked to take part. Your doctor will discuss the treatment with you so that you fully understand the trial and what it involves. You may decide not to take part, or to withdraw from the trial at any stage. You'll then receive the best standard treatment available.
You may experience many different emotions| while having treatment for breast cancer, including anxiety|, anger| and fear. These are all normal reactions and are part of the process many people go through in trying to come to terms with their condition. You may find it helpful to talk things over with your doctor or nurse, or with one of our cancer support specialists|. Family and close friends can also offer support.
This section is based on our HER2 positive breast cancer fact sheet which has been compiled using information from a number of reliable sources, including:
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.