Having trastuzumab (Herceptin)

What to expect

Trastuzumab (Herceptin) is given intravenously (as a drip into a vein) in the arm or hand. You’ll have your treatment as an outpatient either once every three weeks or once a week.

Doses

Trastuzumab is usually given over 90 minutes. If you don’t have any side effects, further doses may be given over 30 minutes.

The first time you receive trastuzumab you’ll need to stay in hospital for several hours so that you can be monitored in case you have a reaction to the drug.

Length of treatment

If you are having trastuzumab to treat primary breast cancer it will probably be given for one year, although studies are looking at the benefits of shorter and longer lengths of time.

If you are given trastuzumab for secondary breast cancer, it can be used as long as it is keeping the cancer under control. This will vary from person to person and your specialist will talk to you.

If you are having trastuzumab over many months you may want to miss one treatment, for example to take a holiday. This is safe to do and you can have your next treatment as planned.

Side effects

Everyone reacts differently to drugs. As trastuzumab affects only cancer cells it has fewer side effects than chemotherapy drugs that also affect healthy cells.

If you’re having both at the same time you may have other side effects from the chemotherapy that aren’t listed here.

Side effects of trastuzumab are more likely with the first one or two treatments and in most cases these will reduce over time.

Common side effects

• Flu-like symptoms - you may have fever, chills and mild pain in some parts of your body shortly after the drug has been given. These are only temporary and can be helped with mild pain relief such as paracetamol.
• Nausea - if you feel sick this is usually mild and temporary and can be treated effectively with anti-sickness drugs.
• Diarrhoea - You may have mild diarrhoea but your specialist or GP can prescribe medicine to help control this.

Less common side effects include headache, dizziness, rash, vomiting or breathlessness. These symptoms are usually very mild and usually only happen after the first treatment.

Heart problems

There’s a small chance that heart problems may occur in patients who receive trastuzumab and so tests of heart function, such as echocardiogram or multiple-gated acquisition (MUGA) scan, are usually carried out before and during treatment.

Heart problems are most often seen when trastuzumab is given at the same time as chemotherapy, especially with a group of drugs called anthracylines, or if the patient already has heart problems before starting trastuzumab.

Only a very small number of patients who receive trastuzumab experience heart problems (such as low blood pressure or palpitations) and these are usually not serious.

If they do occur, you may need treatment for them and your Herceptin and/or chemotherapy may be stopped temporarily.