Chemotherapy involves the use of special drugs to attack and kill breast cancer cells. 

For women with early breast cancer, chemotherapy can prevent breast cancer from recurring by killing any remaining cancer cells that may have spread to other parts of the body at the time of surgery.

For women with advanced breast cancer, chemotherapy can destroy much of the cancer reducing tumour size and symptoms.

On these pages, you'll get more information about:

Having chemotherapy

Some chemotherapy drugs are given as tablets, but more commonly chemotherapy is administered as an "infusion". 

This means the drug is delivered by injection into the bloodstream through a vein, usually at three to four week intervals, known as "cycles". 

If your treatment team is concerned about finding your veins for infusions, you may have a small device called a ‘portacath’ inserted under the skin on your upper chest or arm.  The portacath is a long thin plastic tube which can be left in place over a period of months or even years and is used to inject repeated doses into your blood stream and/or to sample blood.

Chemotherapy infusions usually occur in a hospital outpatient clinic, where you visit as a day patient. 

If you have made a decision to receive chemotherapy be sure to ask about:

  • the course and the drugs being used

  • the length of the course

  • the benefits to you

  • potential side effects.

Chemotherapy drugs

Chemotherapy aims to kill the cancer cells in your body, but will temporarily affect some of your other cells as well.  There are many different chemotherapy drugs and they are often used in combination to provide the most effective treatment. 

Typically you will receive a combination of chemotherapy drugs. These drugs all interfere with the formation and copying of DNA (gene material). They work in different ways and by using them together they are more effective.  The drugs can have a number of side effects, which are almost always temporary and discussed below.

The most common types of chemotherapy drugs are:

Alkylating agents (.eg. cyclophosphamide).  These drugs attach a chemical called an alkyl group (CnH2n+1) to DNA (which forms our genes and chromosomes), and interfere with the process of copying DNA as cells divide. Cancer cells develop with multiple gene mistakes (mutations) which make them less able to repair such DNA damage and lead to them being killed by the chemotherapy. Normal cells that are dividing also suffer temporary damage, but are rapidly repaired. This temporary damage leads to many of the side effects of chemotherapy, which are again almost always temporary.

Antimetabolites (e.g. methotrexate).  These drugs are essentially false building blocks for DNA which are taken up into dividing cells and interfere with the copying of DNA. Again normal cells are readily able to remove these drugs, but cancer cells are often killed.

Anthracyclines (e.g. adriamycin and epirubicin) These were originally isolated from bacteria as natural antibiotics, but they were found to be one of the most active types of chemotherapy ever developed. They interfere with the untangling of DNA and lead to cell death in many types of cancer, but again cause only temporary damage to normal cells. After extensive treatment with these drugs, the pumping strength of the heart can be affected, but your oncologist will check for any risk factors for this rare problem.

Taxanes (e.g. paclitaxel and docetaxel).  These are a new type of drug, originally derived from the bark or needles of yew tree species. They interfere with the separation of chromosomes as cells divide. They can cause some different side effects to other drugs e.g. nerve damage and allergic reactions, which your treatment team will try and prevent.

In recent years a number of innovative new medicines have become available for the treatment of early and advanced breast cancer. However, many of these medicines are not funded in New Zealand. Read more about some of these medicines here.

Side effects of chemotherapy

Each type of drug and combination of drugs may have different side-effects, as the chemotherapy drugs will temporarily damage normal cells as well as the cancer cells.  This damage is often quickly repaired in normal cells, but is not so easily repaired in cancer cells causing them to die.

Below is a list of possible side effects.  Remember, you will not get all of these side-effects and most can be minimised and often prevented from occurring.  Most side effects are predictable in terms of their onset, duration and severity and they are usually reversible.

Your medical oncologist will indicate which side effects are most relevant for you.  Click on the one you are most interested in to find out more about it and what can be done to limit its impact.

Common side effects:
Less common side effects:

Common side effects

Immune suppression and increased risk of certain infections

Chemotherapy drugs reduce the number of white blood cells in your body for a short time, usually the 10 to 14 days after chemotherapy is given.  This means your immune system may be compromised and you may be more susceptible to infection.  You may not be able to fight an infection as well as you normally would and infections can behave more seriously.

If you suffer from a high fever, severe sweats or chills seek medical assistance immediately.  These are signs of a possible severe infection and can be dangerous.

Nausea and loss of appetite

Vomiting and feeling sick are common side effects of chemotherapy.  Anti-emetic drugs can help to ease nausea and these are given just prior to your chemotherapy and sometimes for several days afterwards.

Your doctor will usually start you on an anti-emetic regime that eases nausea for most people. New anti-nausea drugs such as Emend (aprepitant) are available for use in conjunction with those chemotherapy drugs that are more likely to cause sickness and have provided a very effective means of fighting chemotherapy-induced nausea.

One way you can help yourself to try and minimise nausea is to drink plenty of non-alcoholic liquids - more than you usually do.

Hair loss

You may lose your hair depending on the type of chemotherapy programme you undergo.  This can range from mild thinning to complete hair loss.  When the hair grows back it may be thicker and curlier or it may grow back a different colour.

Hair loss can be very distressing.  Some women chose to cut their hair before it falls out, while other use wigs, scarves and hats to cover hair loss. 

In New Zealand, the Government will subsidise the cost of a wig.  For more details go to the Ministry of Health website here for the Wigs and hairpieces subsidy


Chemotherapy often makes women feel tired.  It may take several months after treatment for you to fully recover your energy.

During treatment get as much help as you can with practical tasks.  Get lots of rest, but also remember to exercise. Exercise will actually minimise tiredness and help to prevent weight gain.

Weight gain

Many women may actually gain weight during chemotherapy.  An exercise plan and healthy diet will help to maintain your optimal weight.

Constipation or diarrhoea

Some drugs, particularly antiemectics (or anti-nausea drugs) can cause constipation, while others can cause diarrhoea. 

With both conditions make sure you are drinking plenty of water.  Medication can be taken to treat the symptoms of diarrhoea, while lifestyle changes, such as eating high-fibre foods and getting regular exercise, can help to alleviate constipation.

Disruption to your menstrual cycle

Chemotherapy will often cause your periods to stop for a time or bring about an early menopause (periods stop permanently).  This is because the medication affects the levels of oestrogen in your body which affects the follicles in the ovaries.  Some menopausal symptoms can be unpleasant (e.g. hot flushes, vaginal dryness) so discuss ways to prevent or alleviate these with your medical team.  If you're a younger woman who experiences temporary menopause, you might like to check our fertility page.


Chemotherapy can result in permanent menopause and could impact your fertility if you are of child-bearing age.  If you are planning to have children, talk about fertility issues with your surgeon before you are referred to an oncologist for chemotherapy, as you may wish to discuss these matters with a fertility specialist.  If it is likely you will experience menopausal symptoms – or perhaps experience an early menopause – then it may be helpful to find out more about these changes and how they will affect you.  For more information on preserving fertility see our fertility page.

Less common side effects (often occuring with only one type of drug)

Mouth ulcers

Women undergoing chemotherapy occasionally experience mouth ulcers, throat sores, cold sores and/or thrush. To prevent these  problems make sure you keep your mouth clean.  Your chemotherapy nurse will advise you on the best mouthwash to use.

Joint or muscle pain in arms or legs

Certain chemotherapy medication can cause discomfort in the joints or muscles.  Tell your doctor if you are experiencing this kind of discomfort because you may be able to take a different or additional medication.

Tingling, burning or numbness in hands and feet

These symptoms can occur as the result of nerve damage associated with some chemotherapy drugs, usually taxanes.  Tell your doctor if you have persistent symptoms, as he or she may lower the dose or stop the drugs.

Skin and nail problems

Hyper-sensitive or itchy skin and brittle or cracked nails can occur, but are not usually serious.  Skin can feel sensitive to touch, may appear red and itchy and be more prone to sun damage.  Make sure you protect yourself from the sun and use appropriate moisturisers – ask your breast or chemotherapy nurse for advice. 

Nails may be more prone to infection, especially if they are cracked or brittle.  Keep nails well trimmed and wear gloves when gardening or have your hands in water.

Memory loss

Some chemotherapy treatment can result in minor short-term memory difficulties, often known as "chemo brain". If you are experiencing these symptoms talk to your medical team about what can be done.

Allergic reactions

Allergic reactions may occur when you are given Taxanes. They can be severe in up to three per cent of cases, but are almost always prevented with anti-allergy drugs given prior to treatment.

Heart Damage

In very rare cases, heart damage may occur with certain drugs, such as Adriamycin and epirubicin. The risks are very low unless women have pre-existing heart problems. Make sure you tell your oncologist about any history of heart disease.

Find out more