How does chemotherapy work?

Chemotherapies are anticancer drugs (cytotoxic drugs) that work by killing cancer cells when they start to divide. Chemotherapies for secondary breast cancer are given to stop your cancer growing and reduce your symptoms. They can extend your life and give you a better quality of life.

Chemotherapy is usually given through an intravenous drip or as tablets. It can affect your healthy cells as well as cancer cells – this causes side effects. Your course of chemotherapy (the dose and number of days you take it for) will be planned to have the greatest impact on cancer cells and the least impact on your healthy cells.

How many chemotherapy drugs will I take?

You’re likely to receive a single chemotherapy drug at a time rather than a combination of drugs. This is because there is no proof that taking multiple chemotherapies at once for secondary breast cancer will extend your life more than taking them one at a time, yet taking them together could make the side effects worse.

A time when people might be given a mixture of different chemotherapy drugs is if their cancer is making them extremely unwell and a strong treatment is needed to try to get it their cancer under control fast.

Which chemotherapy drug is right for me?

The chemotherapy you’re offered will be chosen to best suit you.

The chemotherapy you’re offered first will depend on:

  • Which chemotherapies you’ve received already (if any) and how well they worked for you
  • The chemotherapy your oncologist feels may work best based on the characteristics of your cancer
  • Your general health
  • Which side effects you have experienced before with chemotherapy (if any)
  • Which side effects you’d find more manageable
  • Your own preferences (e.g. tablets or a drip, or avoiding hair loss)

It is common for people to begin on a type of chemotherapy called an anthracycline. Examples are doxorubicin or epirubicin.

Alternatively, you may begin with a different type of chemotherapy called a taxane. Examples are docetaxel or paclitaxel. If you have received these before, you’ll have a different chemotherapy such as carboplatin, capecitabine, vinorelbine or gemcitabine.

Your oncologist might suggest switching drugs or reducing the dose of your drug if it is giving you bad side effects. If in the future your cancer begins to grow, your oncologist will recommend switching to a different chemotherapy drug.

Another drug sometimes used to treat later stage secondary breast cancer is eribulin (Halaven), which works by stopping cells growing and dividing.

Another drug sometimes used to treat later stage secondary breast cancer is eribulin (Halaven), which works by stopping cells growing and dividing.

Another drug sometimes used to treat later stage secondary breast cancer is eribulin (Halaven), which works by stopping cells growing and dividing.

Another drug sometimes used to treat secondary breast cancer is eribulin (Halaven), which works by stopping cells growing and dividing. Eribulin (Halaven) is currently only available as standard on the NHS in England, Wales and Scotland, but your oncologist may be able to request a prescription for you. See our section on access to anticancer drugs for more information.

Are there any serious risks with chemotherapy?

All chemotherapies come with a small risk of serious complications, and these differ by drug. For example, some chemotherapies can increase your risk of having a blood clot in a vein (venous thromboembolism), or heart problems.

They can also weaken your immune system, making it more likely that you’ll get a serious infection.

Despite these side effects, many people with secondary breast cancer will benefit from chemotherapy. Many side effects can be treated.

Make sure your oncologist explains the risks of any chemotherapies recommended for you, so you’re informed and can balance this up against the potential benefits.

They should also let you know about the signs of infection such as fever, so that, if you get ill, you know when to seek emergency medical help.

What are the other main side effects of chemotherapy?

The side effects of chemotherapy differ between drugs, but some common side effects are:

  • A sore mouth (this can happen with anthracyclines in particular)
  • Nausea and vomiting (this can happen with anthracyclines and taxanes for example)
  • Fatigue (ongoing tiredness)
  • Hair loss (this is less likely with capecitabine, vinorelbine, gemcitabine and carboplatin)
  • Damage to your nerves (peripheral neuropathy), which can cause numbness, pain or lack of coordination (this can happen with taxanes and vinorelbine in particular)

Make sure you get information from your oncologist or clinical nurse specialist about the side effects you may experience and treatments you can take to help.

What help is available for side effects?

Treatments can relieve some of your side effects. For example, anti-sickness treatments (antiemetics) can prevent vomiting and nausea, and other treatments can help with diarrhoea. It is usual for you to take these treatments alongside chemotherapy to avoid feeling ill.

More information

Find out more about treatments to help with infections, fatigue and pain in our maximising quality of life section.

Advice on getting the best care - anti-cancer drugs

Advice on getting the best care

To help you feel confident you’re getting the best care, you may want to:

  • Ask your oncologist to explain what your treatment options are, and why they are recommending a particular drug for you
  • Ask whether there are any additional options for you, including new drugs, clinical trials and treatment at other centres
  • Go over the risks and benefits of each treatment with your oncologist
  • Speak up if your treatment is giving you side effects – your treatment team can often help by prescribing additional treatment
Tips and advice

Information Standard

Information last reviewed: January 2017

Breast Cancer Now's health information is covered by NHS England's Information Standard quality mark.  Find out how this resource was developed.