Targeted therapies for metastatic breast cancer

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Targeted therapies can slow the growth and spread of cancer or control side-effects. They work by interfering with the biology of the cancer cells. Some drugs are given in tablet form. Others are given into a vein through a drip.

Different drugs work in different ways. 

  • Cancer growth inhibitors block or reduce the amount of chemicals and proteins in your body that help cancer cells to divide and grow. For example, lapatninib (Tyverb®)
  • Monoclonal antibodies may be suitable if you have HER2-positive breast cancer. They target cancer cells that ‘overproduce’ or make too much of a protein called HER2. This protein is found on the surface of some cancer cells. The drugs work by attaching to the HER2 protein and slowing down or stopping the cancer cells growing. Examples include trastuzumab (Herceptin®), pertuzumab (Perjeta®) and antibody-drug conjugate Trastuzumab emtansine
  • CDK4/6 inhibitors are designed to interrupt enzymes that promote the growth of cancer cells. Types of CDK4/6 inhibitors commonly used in treating ER-positive, HER2-negative metastatic breast cancer are Palbociclib (Ibrance), and Ribociclib (Kisqali). Both of these drugs can be given in combination with hormone therapy.

HER2-positive breast cancer

A sample of breast cancer cells can be tested for the presence of HER2. It usually takes 3 weeks to get the results. About 1 in 5 women with breast cancer is HER2 positive. These cancers tend to grow faster than those that are HER2 negative and, like many breast cancers, can recur. Remember if you had cancer before, the HER2 receptors on your cancer cells can change. Your doctor will not know if they have changed until they do a new biopsy.

There is ongoing research looking at different types of targeted drugs for advanced breast cancer.

Side-effects of targeted therapy drugs

Side-effects of targeted drugs will vary depending on the particular drug you are taking. 
They can include:

  • Diarrhoea
  • Nausea (feeling sick)
  • Sore mouth 
  • Anaemia (low red blood cell count), which can make you feel tired and breathless
  • Bleeding and bruising (caused by low platelets in your blood)
  • Risk of infection and fever (caused by a low white blood cell count)
  • Weakened heart muscle and abnormal electrocardiogram 
  • Numbness/ tingling in your hands or feet
  • ‘Chemobrain’ – concentration and memory problems 
  • Hair loss 
  • Rashes and other skin changes
  • Extreme tiredness (fatigue)

Always contact your doctors if you experience any side-effects.

Read more about managing cancer side-effects

For more information

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