Giving hope to those affected
by secondary breast cancer

Research. Support. Education.


10th July 2022 by Jack Allan

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Trastuzumab is a targeted cancer drug also known as Herceptin. 

It is a treatment for early and advanced breast cancer, advanced stomach cancer and cancer of where the food pipe joins your stomach. 


It is a treatment for cancers that have large amounts of a protein called human epidermal growth factor receptor 2 (HER2). 

How does trastuzumab work?


Some breast and stomach cancers have large amounts of human epidermal growth factor receptor 2 (HER2). They are called HER2 positive cancers. HER2 makes the cancer cells grow and divide.


Trastuzumab is a type of targeted cancer drug called a monoclonal antibody. It works by attaching to HER2 so it stops the cancer cells from growing and dividing.


How do you have trastuzumab?


For breast cancer, you might have trastuzumab as a drip into your bloodstream (intravenously) or as an injection under the skin (subcutaneous). If you have trastuzumab intravenously, you may be able to switch to the subcutaneous injection. 


Into your bloodstream

Each treatment takes between 30 and 90 minutes. You have the first treatment over 90 minutes and your team will check you for any side effects. Depending on the effects you have, the next infusion might be shorter.


You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. 

This can be a:


  • central line
  • PICC line
  • portacath


If you don't have a central line, you might have treatment through a thin short tube (a cannula) that goes into a vein in your arm each time you have treatment.


As an injection under the skin

You might have trastuzumab as an injection under the skin, on the upper, outer part of your leg. The injection takes about 2 to 5 minutes.


It is important that your nurse changes which leg you have your injection in each time, to stop the area getting sore. They will check you for side effects for a few hours after the injection.


How often do you have trastuzumab?


As the first treatment for breast cancer that has spread, you might have it together with the chemotherapy drugs paclitaxel (Taxol) or docetaxel (Taxotere) or with hormone therapies called aromatase inhibitors. Open a glossary item


Trastuzumab is also used as a treatment on its own for people who have had at least 2 types of chemotherapy and where hormone therapy has not worked.


You have it every 3 weeks for as long as it is working and the side effects aren’t too bad.




You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.


You will also have a heart trace test (ECG) and a heart scan before you start your treatment. You will have heart tests every few months while you are having trastuzumab and for some time after.


What are the side effects of trastuzumab?


How often and how severe the side effects are can vary from person to person. They also depend on what other treatments you're having. For example, your side effects could be worse if you're also having other drugs or radiotherapy.


Side Effects can include:


  • Risk of infection
  • Breathlessness
  • Bruising and bleeding
  • Allergic reaction
  • Pain in different parts of the body
  • Diarrhoea or constipation
  • Muscle spasms
  • Burning or tingling feeling in hands or feet
  • Hot flushes or sweats
  • Indigestion
  • Heart problems
  • Fatigue
  • Skin and nail problems
  • Mouth sores and ulcers
  • Soreness, redness and peeling on hands and feet
  • Taste changes
  • Tummy pain
  • Blood pressure changes
  • Eye problems
  • Shaking
  • Headaches and dizziness
  • Swollen hands and feet
  • Loss of appetite and weight changes
  • Difficulty sleeping
  • Lung problems
  • A runny nose
  • Feeling or being sick
  • Hair loss or thinning
  • Flu like symptoms