Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. The drugs are carried in the blood, and so can reach cancer cells all over the body. Chemotherapy drugs affect dividing cells. This includes some normal cells such as in the lining of the mouth, the bone marrow (which makes blood cells), the hair follicles, and the digestive system. Healthy cells can repair the damage caused by chemotherapy but cancer cells can’t and so they eventually die.

Chemotherapy can be given in different ways: either as tablets or capsules which are swallowed, or by injection into a vein. There are many technical terms used to describe how the drugs are given and you will see these on your child’s drug chart and on treatment plans (protocols). The common terms are:

• intravenous or IV: injection into a vein
• oral, PO, O or by mouth: as tablets or capsules
• intramuscular or IM: injection into muscle
• subcutaneous or SC: injection just under the skin
• intrathecal or IT: by lumbar puncture.

Whichever way chemotherapy drugs are given, they are absorbed into the bloodstream and carried around the body so that they can reach all the cancer cells. This makes chemotherapy especially useful in treating cancers that are likely to spread, or have spread, to other parts of the body.

Chemotherapy has to be planned carefully. It is usually given as a series of sessions of treatment. Each session destroys some of the cancer cells and will cause some damage to healthy cells. After each treatment, there is usually a rest period so that the healthy cells can recover before the next dose is given. A session of chemotherapy and the rest period is known as a cycle of treatment. A series of cycles make up a course of treatment.

There are many different ways of giving chemotherapy and it may sometimes be given intensively in high doses over a short period or in lower doses over a longer period.

A common way of giving chemotherapy into a vein is through a central line, PICC line or implantable port. These are tubes that are inserted into a vein and can stay in place for some months. They can be used for taking blood as well as giving treatment and other medicines. This means that your child won’t need to have a needle inserted each time, something which can be painful and distressing for a child. The chemotherapy drugs are usually diluted into a bag of liquid such as salt water (saline) and the drip is attached to the end of the central line, PICC line or implantable port.

Occasionally, treatment may be given through a thin tube that is inserted into a vein and then taped firmly to your child’s arm. This tube is called a cannula.

Chemotherapy drugs can cause unpleasant short-term side effects. However, these are mostly temporary and there are often ways of controlling or reducing them. The main areas of the body that may be affected by chemotherapy are where normal cells rapidly divide and grow. These include cells in the mouth, the lining of the digestive system, the skin, hair follicles and the bone marrow.

Some of the common short–term side effects and ways of dealing with them are described here. Your child will not have all of the side effects described, but may have some of them. Side effects of particular chemotherapy drugs are detailed in our chemotherapy section.

Different children will be affected by chemotherapy in different ways. Your child’s doctor or chemotherapy nurse will tell you about the side effects likely to occur during your child’s treatment.

The possible longer-term side effects of chemotherapy are discussed later on in this section.

Low immunity to infection (neutropenia)

Some chemotherapy drugs can reduce the production of white blood cells by the bone marrow. This lowers your child's immunity and makes them more prone to infection. This effect can begin seven days after treatment has been given. If the chemotherapy is being given every 3–4 weeks, the number of white blood cells usually reaches its lowest point (nadir) about 10–14 days after the chemotherapy. The blood cells will then increase steadily and will usually have returned to normal before the next course of chemotherapy is due.

When the white cell count is low your child may become ill with an infection. In spite of this they will be able to overcome most minor infections.

You must contact the hospital straightaway if:

• your child’s temperature goes above a certain level (staff at the hospital will tell you which level)
• your child suddenly feels unwell (even with a normal temperature).

Your child will probably need to be admitted for intravenous antibiotics until the hospital is sure about the type of infection.

Your child will have a blood test before having more chemotherapy to make sure that their cells have recovered. Occasionally it may be necessary to delay treatment if their blood count is still low.

Some infections that usually cause little trouble may be more difficult for your child’s immune system to cope with. Measles and chicken pox can be particularly serious. If your child is exposed to either of these, or develops these infections, let the staff at your child’s specialist hospital know straight away, so that appropriate treatment can be given.

Tiredness or breathlessness

Some chemotherapy drugs lower the number of red blood cells produced by the bone marrow, so your child may become anaemic. This may make them feel very tired and breathless. If the number of blood cells is very low, a blood transfusion can be given.

Bruising or bleeding

Some chemotherapy drugs can reduce the production of platelets, cells which help the blood to clot. Let your doctor know if your child has any unexplained bruising or bleeding such as nosebleeds, blood spots or rashes on the skin, or bleeding gums. If the number of platelets in the blood is very low, a platelet transfusion can be given.

Feeling sick

Chemotherapy drugs may make your child feel sick (nauseated). Some drugs may make your child actually be sick (vomit). However, this can often be controlled with anti-sickness medicines known as anti-emetics. Tell the doctors if your child is having problems with sickness – changing the anti-sickness medicine can usually help.

Loss of appetite

Sometimes your child may not feel like eating and they may temporarily lose weight. Try giving them their favourite foods and don’t worry if they keep eating the same thing. Having smaller meals but eating more often can also help.

If needed they may be fed through a tube passed down their nose into their stomach (nasogastric tube), or a tube passed through their abdominal wall into the stomach (PEG tube). Sometimes, they may be fed through a central line.

Diarrhoea or constipation

Some drugs may change the way that the bowel works, so your child may have diarrhoea or constipation. Laxatives can be given for constipation. Diarrhoea can usually be controlled with anti-diarrhoea medicines.

Sore mouth

Some drugs can cause a sore mouth, which may lead to mouth ulcers. If this happens it usually starts about 5–10 days after the drugs are given and will clear up within 3–4 weeks. Your child’s doctor can prescribe mouthwashes to help and the nurses will show you the best way to care for your child’s mouth.

Taste changes

Chemotherapy can cause your child’s taste to change; food may taste more salty, bitter or metallic. Their taste will return to normal after the chemotherapy treatment finishes.

Skin changes

Some chemotherapy drugs can cause skin rashes or a change in the colour of the skin. The skin may also become more sensitive to chemicals such as the chlorine in swimming pools.

Your child’s skin may be more sensitive to the sun. Protect your child’s skin from the sun by getting them to wear a hat and sunglasses, covering skin with loose clothing and using sunscreen cream on any exposed areas.

Hair loss

Some drugs will make your child’s hair fall out. In some children all their hair may fall out, but in others the hair may just get thinner. There are lots of ways of dealing with hair loss - often children like to wear baseball caps, bandanas, hats or scarves rather than have a wig. But if you and your child want, a wig will be given to them by staff at the hospital. The hair always grows again quite normally within a few months of stopping treatment.

Kidney, liver or heart damage

Some drugs cause a change in the way that the kidneys, liver or heart work and this may be long-term. Your child will have regular tests to check that their kidneys, liver and heart are working properly.

Behavioural changes

Some drugs can cause feelings of anxiety, restlessness, dizziness, sleeplessness or headaches. Some children also find it hard to concentrate on anything. If your child has any of these side effects, let your doctor know.