Explanation

Trastuzumab (also called Herceptin®) is a medicine that is used to treat breast cancer.

What does trastuzumab do?

When someone has just started with breast cancer, trastuzumab helps to stop it from getting worse. It can also be used if the cancer has spread to other parts of the body.

Trastuzumab is an antibody that has been specially made to stick to breast cancer cells and stop them from growing.

Trastuzumab can be used by itself or with other medicines to treat breast cancer .

What does it look like?

Trastuzumab comes as a white or pale yellow powder in a small bottle. This powder is mixed with water and given to people through a tube that a doctor will put into a vein in one of their arms. This is called an intravenous drip.

When does it have to be taken?

People have to go into hospital to have trastuzumab treatment.

How often someone is treated depends on how much they weigh and how ill they are. Their doctor will decide the perfect dose for them. They may need to go to hospital for trastuzumab every week, or it could be every 3 weeks.

It usually takes between 30 and 90 minutes each time for all of the trastuzumab to get through the tube and into the body.

But what if someone doesn't feel like taking it?

People who are having trastuzumab need to keep going for treatment for as long as their doctor tells them to, even if they don't feel like it. Trastuzumab will help to make sure that the breast cancer doesn't grow quickly.

What should someone do if they forget to go and have their trastuzumab treatment interrupted?

Going to have trastuzumab is very important, because trastuzumab will help to slow down the growth of breast cancer.

If someone can't go for treatment when they are supposed to, they must talk to their doctor to arrange another time to go.

What are the most likely side effects that someone might get?

Not everyone gets side effects from trastuzumab, and also people are more likely to have some side effects than others. People should tell their doctor if they notice any.

When someone is in hospital having trastuzumab, it is quite likely that they will have symptoms like a fever or feeling cold. These usually don't last for very long though, and normally only happen the first time that someone has trastuzumab treatment.

Side effects that people could get at any time while having trastuzumab include:

pain in their chest or abdomen

Headache

Diarrhoea (runny poo)

Tiredness

Skin rashes

Pain in joints or muscles.

What other side effects might someone get?

Other side effects that someone could get if they are having trastuzumab treatment include:

An allergic reaction

Problems with the number of cells in their blood

Heartburn or indigestion

Constipation

Infections, including in their bladder and skin

Tight muscles

Shakiness

Problems sleeping

Feeling too tired

Nose bleeds

Acne

Feeling itchy

Feeling confused

Dizziness

Losing weight

Not feeling hungry

Asthma

Pain in their neck or back

Pain in their bones

Pains in their legs

Bruising

Arthritis

Piles (an itchy or sore bum)

Things tasting strange

People should tell their doctor about any side effects immediately.

Are there any other side effects that you haven't already mentioned?

There are a few more side effects that people could get. While in hospital having trastuzumab treatment someone may:

Feel or be sick

Get a headache

Cough or wheeze

Have a shakiness or more tension in their muscles

Get a rash

Have a swollen face or mouth

Feel tired

If any of these happen, the doctor will slow down or stop the treatment. If the side effects are very bad, the doctor might give the person medicine to make them better. When the side effects get better, they might be able to have trastuzumab treatment again.

Sometimes trastuzumab causes heart problems. These can be very bad, so when someone is being treated with trastuzumab their doctor will monitor their heart. They should tell their doctor immediately if they:

feel out of breath

feel their heart fluttering or feel it beating differently from usual

get a cough

have swelling in their arms or legs

Is it safe to take trastuzumab?

Before someone takes trastuzumab, they should tell the doctor about any other medical problems that they know they have. If they have any shortness of breath, they must tell their doctor straight away.

If someone has heart problems, trastuzumab can make them worse. People should tell their doctor if they have ever had:

heart failure

heart disease

High blood pressure

They must also remember to tell their doctor if they have any allergies - to trastuzumab or anything else. Trastuzumab contains trehalose (a type of sugar) and proteins from mice.

Is it ok for someone to take trastuzumab if they are already taking other medicine?

Someone must tell their doctor if they're taking anything for other medical problems, including drugs, special foods or herbal remedies.

Trastuzumab shouldn't be used with another type of medicine used to treat cancer called anthracyclines. Examples of anthracyclines include doxorubicin and daunorubicin.

Trastuzumab stays in the body for 6 months. If someone starts taking any new medicines within 6 months of treatment, they must make sure they tell the doctor that they have recently had trastuzumab.

Is there anything else people should know about trastuzumab?

If a woman is pregnant, she should tell her doctor before she starts trastuzumab treatment.

Before babies are born, they are surrounded by a special liquid to protect them. This is called amniotic fluid. Very rarely, trastuzumab can reduce the amount of this fluid, so pregnant woman should ask their doctor for more advice about this.

Women shouldn't breast feed their baby for 6 months after they were last treated with trastuzumab.

What if I have any more questions?

If you have any other questions, you can ask your doctor, or chat to other people whose lives have been affected by breast cancer in the Medikidz forums and virtual world, Mediland.