Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells that are found in the body. There are many types of chemotherapy drugs so the type, dose, length of treatment and administration method will be defined by the child’s cancer diagnosis. The administration methods vary, but the most common is intravenously (through the vein).
Cancer is made from cells that are dividing abnormally, so chemotherapy works by targeting dividing cells. However, chemotherapy can also affect dividing cells that occur naturally in all children as part of the growing process, such as those in the bone marrow, the hair and the digestive system.
How children react to chemotherapy will depend on the child. In the short-term children may show signs of hair loss, tiredness, bruising or bleeding, sickness & diarrhoea, mouth sores & taste changes, skin changes and behaviour changes. Some of these short-term side-effects will require complementary treatments such as a blood transfusions
The long-term effects of chemotherapy again depend on the child and the types of chemotherapy drugs administered. Long-term effects may become apparent during treatment or may occur later in life, and therefore survivors may require regular tests after they are designated cancer free 1
Long-term effects can include damage to the digestive system and lungs as well as:
Damage to heart– cardiovascular events are the commonest cause of non-malignant death in childhood cancer survivors. A study by the CCSS showed survivors had a six-fold risk of an adverse cardiac event compared to sibling controls2.
Damage to the nervous system – chemotherapy drugs, Vincristine and Cisplatin are associated with the development of peripheral neuropathy (damage to nerves that can impair sensation, movement, gland and organ function). Other effects of chemotherapies can include seizures2.
Damage to the ear – some chemotherapy treatments such as those using platinum compounds can cause hearing loss due to damage to the cochlear hair cells. If significant this can lead to effects on speech development, leading to educational and social difficulties2.
Damage to the reproductive system – A number of chemotherapy drugs can affect the reproductive system leading to infertility or in females – early menopause. Most commonly the chemotherapy drugs classed as alkylating agents, including cyclophosphamide, ifosfamide, busulfan, melphalan and the nitrosoureas (lomustine and carmustine) are most damaging. 2.
Damage to bone health – Cancer treatments can affect bone growth leading to long term issues, including early onset osteoporosis and increased risk of fracture. Symptoms can include minimal pain to disabling pain and immobility2.
Damage to the teeth – Chemotherapy can increase the risk of dental abnormalities later in life, especially in those who receive treatment before they grow their adult teeth.2.
Risk of secondary cancers – Secondary cancers are the commonest cause of death following treatment for childhood cancer. Reports suggest that the risk of developing a second malignancy is 3–6 times that which would be expected in the general population.2.
Chemotherapy is one of the main treatments for children diagnosed with cancer. However further research is needed to create safer chemotherapies that do not cause many of the late-effects that are currently associated with this treatment.
One exciting area of research is personalised medicine which studies an individual’s genes in order to identify the type of cancer and the treatment most likely to cure the child. It also identifies treatments the individual will be least resistant too – or least susceptible to its side effects.