Why does chemotherapy cause side-effects?
Chemotherapy targets cancer cells, which are unhealthy cells that divide and reproduce quickly. Chemotherapy can also affect healthy fast-growing cells within the body. These are cells which live in the stomach, mouth, skin, hair and bone marrow. Most side-effects are associated with these areas of the body.

Doctors will be able to explain what drugs are being given and what the likely side-effects could be. They may also be able to prescribe other medicines to keep any side-effects to a minimum to make the child as comfortable as possible. Not all children experience side-effects. It is also important to remember that they tend to stop soon after treatment.

Below is a list of the more common side-effects and the possible ways the care team may be able to help.

        • Sickness Chemotherapy drugs can make a child feel, or be sick. The doctor can prescribe anti-sickness drugs.
        • Diarrhoea and Constipation Chemotherapy drugs can affect the bowel, changing the way it works.  This can be helped by laxatives or anti-diarrhoea drugs.
        • Mouth ulcers and taste changes A number of chemotherapy drugs can cause a sore mouth, or mouth ulcers to develop. This can happen within a week of starting treatment. Most cases clear within four weeks. The child may also experience a metallic or bitter taste in their mouth, which should return to normal at the end of the treatment. Good dental hygiene is recommended and it is important to report mouth ulcers to a medical professional.
        • Hair loss This is often the side-effect most people associate with cancer treatment.  For some children, all of their hair may fall out. For others, it may become very thin. The hair will begin to grow back once treatment has stopped. 
        • Skin problems Chemotherapy drugs can make a child's skin very sensitive to the sun, so  it should be protected from the sun and from other chemicals such as chlorine in swimming pools. Rashes and even colour changes can occur.  

Effects on the blood
Because chemotherapy attacks rapidly reproducing cells, it can cause the number of blood cells within a child’s body to drop. This is known as a child’s “blood count”. (For example, the Consultant may say your child’s “blood count” has dropped.)  The blood count is usually at its lowest 10 days into treatment but then steadily increases after that. Blood cells are produced within the bone marrow which is a spongy material found in the middle of certain bones. The bone marrow is the ‘production factory’ for blood. The blood consists of red blood cells which carry oxygen, white blood cells which fight infection, and platelets which clot the blood to prevent bleeding and bruising .
• Red blood cells A low number of red blood cells is called ‘anaemia’. Chemotherapy can reduce the number of red blood cells produced by the bone marrow, making a child ‘anaemic’. This can cause symptoms such as tiredness, breathlessness and dizziness.  If a child becomes anaemic this is usually a short-term condition which can, if necessary be treated with a blood transfusion.
• White blood cells Some chemotherapy drugs can reduce the number of white blood cells in the blood, which can make a child prone to infection. This is known as having a “lowered immunity”. A blood transfusion cannot be given to replace white blood cells so treatment may be temporarily stopped until the white cell count rises naturally.
There are three types of white blood cells, called Neutrophils, Lymphocytes and Monocytes. During treatment, doctors are most concerned about Neutrophils. If the child’s blood sample shows a very low number of Neutrophil cells, they are ‘Neutropenic’.

A reduction of white blood cells means that a child may become ill through any - even minor - infection (such as a cold). It is important for parents to contact their child's Consultant if the child develops a temperature or feels poorly. This is so the infection can be treated quickly to prevent it from becoming serious. The child will probably be treated in hospital with antibiotics.

Platelets A low number of platelets in a child’s blood sample is known as ‘Thrombocytooenia’. If this happens a doctor may say that a child is ‘Thrombocytopenic’. This may cause the child to bruise easily or to bleed for longer if they cut themselves. If the number of platelets in a child’s blood sample falls very low, they may require a platelet transfusion.

It may seem like there are an overwhelming number of possible side-effects associated with chemotherapy. If parents are concerned about them they can  talk to their Consultant who can describe which ones are associated with which drugs. It is important to remember that most side-effects stop once treatment is over.

Source: www.clicsargent.org.uk