The exact cause of most childhood leukaemias is unknown and there are no known risk factors. It seems likely that it is caused by chance mutations in the genes of white blood cells.
Treatment for leukaemia varies based on a child’s risk level, which examines factors such as age, overall health, and type of leukaemia. Treatment usually begins by treating the early symptoms which can include anaemia, bleeding and/or infection. Chemotherapy is the main treatment for most childhood leukemias.
What Role Does DNA Play In Childhood Leukaemia?
Changes in the DNA inside normal bone marrow cells can cause them to grow out of control and become leukaemia cells.
DNA is the chemical in our cells that makes each person unique and carries the instructions for the development, growth, reproduction, and functioning of all life.
Two kinds of genes manage when our cells grow, divide into new cells, and die at the right time:
- Genes that help cells grow, divide, or stay alive are called oncogenes.
- Genes that help manage cell division or cause cells to die at the right time are called tumour suppressor genes.
Cancers can be caused by DNA mutations that keep oncogenes turned on, or that turn off tumour suppressor genes.
These gene changes can be inherited from your parents, or they can occur randomly during a person’s lifetime if cells in the body malfunction when they divide to make new cells.
A common type of DNA change that can lead to leukaemia is known as a chromosome translocation. This genetic abnormality occurs when a chromosome breaks and either the whole or a portion of it reattaches to a different chromosome. Chromosome translocation is seen in nearly all cases of childhood chronic myeloid leukemia (CML) and in some cases of childhood acute lymphocytic leukemia (ALL).
What Are Inherited and Acquired Gene Mutations?
Childhood leukaemias are occasionally caused by inherited gene mutations. In most cases leukaemia appears to develop (is acquired) during conception or childhood. Some studies also suggest that some childhood leukemias may be caused by a combination of genetic and environmental factors.
Inherited Gene Mutations
Certain inherited conditions can increase the risk of developing leukaemia. Rarely, children inherit DNA mutations from a parent that increase their risk for cancer. For example, an inherited mutation of a tumour suppressor gene can increase a child’s risk of developing leukaemia, as well as some other cancers.
Acquired Gene Mutations
Most childhood leukaemias do not appear to be caused by inherited mutations. Usually, acquired DNA mutations related to leukaemia develop after conception for no apparent reason. In rare cases, acquired mutations can result from exposure to cancer-causing chemicals or radiation.
Combination Of Genetic And Environmental Causes
Ongoing research suggests that many childhood leukaemias may be caused by a combination of genetic and environmental factors. For example, some children do not have healthy versions of genes that control how our bodies break down and get rid of harmful chemicals. These children may not be able to break down harmful chemicals if they are exposed to them. This combination of genetics and exposure might increase their risk of developing leukaemia.
Certain childhood leukaemias might also be caused by a combination of certain gene mutations that happen very early in life, along with being exposed to certain viruses at a later age. This “delayed infection” (after the first year of life) may affect the immune system, causing leukaemia to develop.
What Factors Affect Leukaemia Treatment Options?
After leukaemia has been diagnosed and tests have confirmed the type and subtype of leukaemia, the child’s cancer care team will discuss the best treatment options available.
The most important factor in choosing a treatment is the type of leukaemia, but other factors also play a role, including:
- The child's age
- The child’s overall health and medical history
- How well the child can tolerate the treatment
- How the disease has progressed
- How the disease is expected to progress
How Is Childhood Leukaemia Treated?
Initially treatment will focus on the child’s first symptoms. These often include anaemia (a lack of red blood cells), bleeding (from bruising) and infection. Follow-up care is vital to help the doctor gauge how well treatment is working.
Treatment for leukaemia may include any of the following options:
Chemotherapy are potent medicines that are given by mouth or intravenously that kill cancer cells. Side effects are common because these powerful drugs can also harm some healthy cells.
Methotrexate is a chemotherapy drug that is used to treat certain types of cancer and leukaemia. It is given intrathecally, which means that it is injected into the spine. It prevents leukaemia cells entering the cerebrospinal fluid (CSF) around the spine and brain and can also be used to treat leukaemia found in the CSF.
Radiation therapy is occasionally used to prevent or treat the spread of leukaemia to the brain or treat the testicles in boys. It can also help with pain from a swollen liver, spleen or lymph nodes and can relieve pain from bone marrow expansion.
Blood And Bone Marrow / Stem Cell Transplantation
Initially, high-dose chemotherapy (and perhaps radiation) is given to destroy the cancer cells in the bone marrow. Donor stem cells are then given by IV to replace the bone marrow cells that have been killed by chemotherapy. These fresh, healthy stem cells make their way to the bone marrow where they start making normal white blood cells, red blood cells and platelets.
Biological / Immunological Therapy
Immunotherapy (sometimes called biologic therapy) is a type of treatment that helps a person's immune system fight cancer. Antibodies against the cancer cells are given that may help the body’s immune system find and kill cancer cells.
Drugs to prevent or treat the side effects of leukaemia treatment may be given, e.g. for nausea or pain.
Blood transfusions might be necessary to replace red blood cells and / or platelets.
Medicines may be given to prevent or treat infections.