Chemotherapy (sometimes just called "chemo") is the use of drugs to kill or slow the growth of cancer cells. The drugs are called cytotoxics, which means toxic to cells (cyto). Some of these drugs come from natural sources such as plants, while others are completely made in a laboratory.

How it works

All cells in the body grow by splitting into two cells or dividing. Chemotherapy damages cells that are dividing rapidly. Most chemotherapy drugs enter the bloodstream and travel throughout the body to target rapidly dividing cancer cells in the organs and tissues. This is known as systemic treatment. Sometimes chemotherapy is delivered directly to the cancer. This is known as local chemotherapy.

How chemotherapy is used

You might have treatment with a single chemotherapy drug or a combination of several drugs. There are many different types of chemotherapy drugs, and each type destroys or shrinks cancer cells in a different way.

The chemotherapy drugs you have depend on the type of cancer. This is because different drugs work on different types of cancer. Sometimes chemotherapy is the only treatment needed, but you may also have surgery, radiation therapy or other drug therapies.

Reasons for having chemotherapy

Chemotherapy can be used for different reasons:

To achieve remission or cure

In many cases, chemotherapy causes the signs and symptoms of cancer to reduce or disappear (often referred to as remission or complete response). The treatment may be called curative chemotherapy.

To help other treatments

Chemotherapy is sometimes given either before or after other treatments. If used before (neoadjuvant therapy), the aim is to reduce the cancer so the other treatment is more effective. If chemotherapy is given after the other treatment (adjuvant therapy), the aim is to get rid of any remaining cancer cells. Chemotherapy is often given with radiation therapy to make the radiation therapy more effective.

To control the cancer

Even if chemotherapy cannot achieve remission or complete response (see above), it may be used to control the cancer's growth and stop it spreading for a period of time. This may be called palliative chemotherapy.

To relieve symptoms

By shrinking a cancer that is causing pain and other symptoms, chemotherapy can improve quality of life. This is also called palliative chemotherapy.

To stop cancer coming back

Chemotherapy might continue for months or years after remission. This is called maintenance chemotherapy, and it may be given with other drug therapies. It aims to prevent or delay the cancer returning.

Chemotherapy and pregnancy

Being diagnosed with cancer during pregnancy is rare. In Australia, about one in 1000 women is affected. 1

While it is possible for some women to have chemotherapy during pregnancy, sometimes chemotherapy and other cancer treatments are delayed until after the baby's birth. Your medical team will discuss all of the available treatment options with you. Their recommendations will be based on the type of cancer you have, its stage, the other treatment options, and how to avoid harming your developing baby.

Having chemotherapy in the first trimester (12 weeks) may increase the risk of birth defects, but there seems to be a lower risk in the later stages of pregnancy. Studies on babies exposed to chemotherapy in the womb during the second and third trimesters show that chemotherapy did not affect their development. 2

However, chemotherapy drugs may affect a developing baby in other ways. For example, chemotherapy may cause premature delivery, and preterm babies often have other health issues, such as respiratory problems.

If you have chemotherapy during pregnancy, you will probably be advised to stop having it at least 3–4 weeks before your delivery date. This is because the side effects of chemotherapy on your blood cells increase your risk of bleeding or getting an infection during the birth. Stopping chemotherapy allows your body time to recover from the side effects. Your doctor can talk in detail about your specific situation and what is best for your health and your unborn baby.

Many pregnant women with cancer feel anxious about the potential impact of treatment on their unborn child. It may be easier to cope if you are well informed about treatments and side effects.

Treatment costs

Chemotherapy drugs are expensive. People do not pay for intravenous chemotherapy received in a public hospital as the cost is covered by the Pharmaceutical Benefits Scheme (PBS). People have to contribute to the cost (co-payment) of oral chemotherapy drugs. You will usually have to pay for any medicines that you take at home to relieve the side effects of chemotherapy (such as anti-nausea medicine). Ask your specialist or treatment centre for a written quote that shows what you will have to pay.

If you have private health insurance and elect to be treated as a private patient, you may have to pay for out-of-pocket expenses and contribute to the cost of the chemotherapy drugs. Check with your doctor and health fund before you start treatment.

Expert content reviewers:

Dr Prunella Blinman, Medical Oncologist, Concord Cancer Centre, Concord Repatriation General Hospital, and Clinical Senior Lecturer, Sydney Medical School, The University of Sydney, NSW; Gillian Blanchard, Oncology Nurse Practitioner, Calvary Mater Newcastle, and Conjoint Lecturer, School of Nursing and Midwifery, The University of Newcastle, NSW; Julie Bolton, Consumer; Keely Gordon-King, Psychologist, Cancer Council Queensland, QLD; John Jameson, Consumer; Dr Zarnie Lwin, Medical Oncologist, Royal Brisbane and Women's Hospital, and Senior Lecturer, School of Medicine, The University of Queensland, QLD; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Dr Felicia Roncolato, Medical Oncology Staff Specialist, Macarthur Cancer Therapy Centre, NSW..

1. YY Lee et al., “Incidence and outcomes of pregnancy-associated cancer in Australia, 1994–2008: a population-based linkage study”,  BJOG: An International Journal of Obstetrics and Gynaecology, vol. 119, no. 13, 2012, pp. 1572–82.

2. FA Peccatori et al., “Cancer, pregnancy and fertility: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up”,  Annals of Oncology, vol. 24, suppl. 6, 2013, pp. vi160–70.

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