Herceptin is the brand name of a medicine called trastuzumab and is used in the treatment of some types of breast cancer and stomach cancer.

HER2-positive cancers

Herceptin is only recommended for people whose cancer is associated with a protein called human epidermal growth factor receptor 2 (HER2). These are known as HER2-positive cancers.

It is estimated that around one in five cases of breast cancer and stomach cancer are HER2-positive.

HER2 is present in all human cells, but in cases of HER2-positive cancers the levels are unusually high.

High levels of HER2 are known to stimulate the growth of these types of cancer, so herceptin works by blocking the effects of the protein. At the same time it encourages the immune system (the body’s defence against infection) to attack the abnormal cells.

When is it used?

Herceptin can be used:

• during the early stages of breast cancer, following surgery and/or radiotherapy and chemotherapy, to reduce the risk of the cancer re-occurring
• for advanced breast cancer that has begun to spread out of the breast (metastatic breast cancer) – it can be given as a single treatment or used in combination with chemotherapy
• for advanced stomach cancer that has started to spread out of the stomach (metastatic stomach cancer)

Herceptin cannot cure metastatic breast and stomach cancers, but it can slow their growth and increase survival time.

How is it given?

Herceptin is given using a process called infusion. The medication is slowly fed into the body via a drip attached to a blood vessel.

This is usually carried out at a hospital or clinic, and a session typically lasts around an hour. The number of sessions you need will depend on the type of cancer you have and how advanced it is. The first session will be longer, as you will be monitored for any unusual reactions to herceptin.

On average, you will need a session once every three weeks for early breast cancer and weekly sessions if your cancer is more advanced.

Stomach cancer is usually treated with a session once every three weeks.

For most people the course of treatment lasts for one year.

Cautions

Herceptin can cause heart problems, so it is not usually recommended for people with pre-existing heart problems or poorly controlled high blood pressure.

If you need to take herceptin your heart will be tested regularly to make sure there are no problems.

It is unclear whether herceptin is completely safe to use during pregnancy. As a precaution it is only recommended in cases where the benefits of treatment strongly outweigh any potential risk to the baby.

Side effects

Most people experience side effects immediately after the infusion that usually pass after a few hours. The side effects tend to become milder and less frequent the more infusions a person has.

Commonly reported side effects (affecting more than 1 in 10 people) include:

• an inital flu-like reaction to the medication that can cause feelings of sickness (nausea), headache, chills and a high temperature
• tremor (uncontrollable shaking and trembling)
• redness, itching and wateriness of the front of the eyes (conjunctivitis)
• changes in blood pressure – this can either be an increase in blood pressure or a decrease
• irregular heartbeat
• you start noticing your heart beating inside your chest (palpitations)
• hot flushes
• coughing
• wheezing
• shortness of breath
• nosebleeds
• diarrhoea
• feeling sick
• being sick 
• abdominal pain
• an itchy red rash can develop on the skin

Ask the doctor in charge of your care for more advice if one or more side effects become particularly troublesome. Medicines are available to treat some of the side effects of herceptin.

Read more in our Herceptin Medicine Guide.