Breast cancer

Targeted therapy

Breast cancer

Targeted therapy star_border Save this page

Targeted therapies are drugs used to treat some cancers. They target specific molecules in the cancer cells that control how these cells grow and multiply.  

Some breast cancers can be treated with targeted therapies.

What you need to know

What is targeted therapy?

Targeted therapy affects specific molecules involved in cancer growth. These are known as molecular targets.

Most molecular targets are genes or proteins. They can be located inside or on the surface of cancer cells, or in the area around the cancer. 

There are several types of targeted therapy that act in different ways, including:

  • blocking the chemicals that tell cells to grow
  • stopping blood flow to the cancer
  • changing the way cancer cells work and causing them to die
  • delivering toxins directly into the cancer cells.

Targeted therapy may be used alone or in combination with other treatments.

Will targeted therapy work for me?

Targeted therapies are only suitable for some cancers because not all cancers have molecular targets.

Targeted therapies also work better for some people than for others. This is because not all cancers with targets respond to treatment with a targeted therapy. Sometimes the cancer will stop growing or get smaller, and sometimes there will be no response.

Your doctor may send a sample of your cancer to be tested for possible targets. If a target is present you may be able to have treatment with a targeted therapy. Different cancers can have different molecular targets, which are treated with different targeted therapies.

Targeted therapy for breast cancer

Some breast cancers have high levels of human epidermal growth factor receptor 2 (HER2). This is a protein found on the surface of the cancer cells. These cancers are called HER2 positive cancers.

HER2 positive cancers can be treated with drugs called HER2 inhibitors. They include:

  • trastuzumab (Herceptin) – given by injection into a vein (intravenous) or just under the skin (subcutaneous)
  • pertuzumab (Perjeta) – given by intravenous infusion
  • lapatinib (Tykerb) – given as a tablet.

What to ask or talk about

Side effects of targeted therapy

Traditional chemotherapy drugs affect cells that are dividing quickly. This includes many normal cells as well as cancer cells.

Targeted therapies only affect certain types of cells, so they do not affect as many normal cells as chemotherapy drugs. This means that the side effects they cause are not like those caused by chemotherapy.

The side effects of targeted therapy depend on which targeted therapy you are given but also vary from one person to another.

Some possible side effects of targeted therapies are listed below:

  • sensitivity to sunlight – dry, red or itchy skin
  • skin rash that looks like acne
  • tenderness and blistering of the palms and soles (hand-foot syndrome)
  • fatigue
  • diarrhoea
  • muscle, bone and joint pain
  • peripheral neuropathy
  • high blood pressure
  • low blood counts
  • bleeding or blood clots
  • slow wound healing
  • changes to the way the heart works.

Ask your doctor, nurse or pharmacist what side effects to expect, and how to manage them.

checklist Checklists

Use our checklists to find helpful tips or questions to ask.

Next steps

Preparing for targeted therapy

Before starting a targeted therapy you may need to sign a consent form. It is important to understand what you are consenting to.

Some other important things you should know are:

  • whether you need any tests before your treatment
  • whether you need to change your diet or medications
  • if you need to take any premedication (tablets you take before your treatment)
  • how you will have your treatment, e.g. as a tablet or in a drip
  • whether you need to take some time off work
  • if you can drive or catch public transport after treatment. 

You may need medicines to manage side effects. It is best to get these before you start treatment, and know what they are for and how to take them. You should also have a thermometer and know how to use it.

Make sure you know who to contact and on what number if you have any concerns or become unwell and if there is a different number at nights or weekends.

Where to get help

There are people you can talk to for more information or support.

My notes: