To mark Childhood Cancer Awareness Month, we’re taking a look at common childhood blood cancer Acute Lymphoblastic Leukaemia (ALL) and the research being carried out by WA scientist Dr Laurence Cheung.
Every year, around 370 people are diagnosed with Acute Lymphoblastic Leukaemia in Australia. Of these, more than 200 are children under 15, and most between the ages of 1–4. Overall, it is the most common type of cancer diagnosed in children in Australia.
Acute Lymphoblastic Leukaemia is a type of cancer that occurs in the blood . Blood is responsible for distributing oxygen and nutrients all around the body and for removing waste products, which is why healthy blood is crucial to your overall wellbeing. When something goes wrong with your blood, the impact can be far reaching.
Blood is made up of three types of cells:
- White blood cells (immunity cells, protecting against infection and disease).
- Red blood cells (transport oxygen to the body’s tissues in exchange for carbon dioxide, which is eliminated by the lungs).
- Platelets (form clots to stop/prevent bleeding).
These cells are formed in the spongy bone marrow in the centre of the bones and carried around the body in a clear fluid called plasma. They have a limited lifespan and need to be continually replaced.
All three types of cells start out in the bone marrow as stem cells. These are unspecialised blood cells that first develop into immature cells known as blast cells. The blast cells mature to become red or white blood cells or platelets and carry out their set functions. If they do not mature properly, or if they grow out of control, they can cause leukaemia.
ALL develops when the body has too many lymphoid blast cells. Under normal circumstances, these would mature to become specialised white blood cells known as B-cells and T-cells. When they grow in an uncontrolled way, they are referred to as leukaemia cells. ‘Acute’ refers to the fact that the leukaemia (blood cancer) can progress quickly and is likely to be fatal if not treated.
The leukaemia cells are immature and abnormal, so they don’t fight off disease in the way that white blood cells should. Instead, they overcrowd the normal white blood cells, preventing them from doing their job. This means the body doesn’t have any way to protect against illness.
As these cells continue to multiply they fill the bone marrow, leaving little room for healthy red cells and platelets. The leukemia cells then quickly invade the blood and can spread to the lymph nodes, liver, spleen, central nervous system, testicles, and other parts of the body.
Who is at risk of developing ALL?
ALL occurs in both children and adults, although it is more commonly diagnosed in boys. The exact causes of ALL are not fully understood, however some factors increase the chance of developing the disease, such as:
- Previous exposure to chemotherapy/radiation
- Genetic disorders (eg: Down syndrome and Fanconi anaemia)
- Long term exposure to some chemicals (benzene, petroleum, paints, pesticides and heavy metals)
- Viruses (Delayed exposure to common childhood infections or an abnormal immune response to these infections may increase risk of developing ALL. Exposure to the Epstein-Barr virus may also increase risk.)
Symptoms of Acute Lymphoblastic Leukemia
ALL develops quickly in children, so they are likely to be unwell for just days or weeks before they are diagnosed. Symptoms can include:
- Anaemia – Look out for lack of energy; persistent tiredness; pale complexion; weakness; dizziness; shortness of breath during physical activity
- Increased bruising/bleeding – Bruising may occur for no apparent reason, or excessive bleeding following minor injury. Look out for frequent nosebleeds, bleeding gums and flat pinhead sized spots (caused by tiny bleeds under the skin)
- Frequent infections – Minor skin infections, a sore throat, sore mouth, slow healing of minor cuts and grazes, coughing, urinary tract infections, persistent low grade fever
- Bone pain
- Swollen lymph nodes (glands),
- Chest pain
- Abdominal discomfort
There are lots of reasons why your children might exhibit the above symptoms that are not related to leukaemia. However, if you have any concerns you should speak to your GP.
If your child frequently bruises or bleeds, is tired all the time, complains of dizziness, or has frequent infections, you should schedule an appointment with a doctor to see if there is a serious underlying problem.
The fastest and easiest way to search for and book healthcare appointments is to do it online through MyHealth1st.
Diagnosing Acute Lymphoblastic Leukemia
ALL is diagnosed by examining samples of your blood and bone marrow. The first step in the diagnosis is a simple blood test , which will indicate whether or not your child has a low red cell and platelet count, and if the white blood cells may be abnormal leukaemic blast cells.
If the results of the blood tests suggest ALL, a bone marrow biopsy will be taken. The doctor will make a small incision under local anaesthetic then insert a hollow needle through the bone and into the bone marrow, withdrawing a sample of the liquid portion of the bone marrow. This is often taken from the back of the hip bone. The sample will then be sent to a lab for testing.
The diagnosis of ALL is confirmed by the presence of an excessive number of blast cells in the bone marrow. Further tests may be required to understand if the cancer has spread.
Treatment for Acute Lymphoblastic Leukemia in Children?
Children diagnosed with ALL need to be treated quickly because of the risk of rapid spread.
The type of treatment your child receives will depend on a number of factors, so it’s best to discuss these fully with your doctor. There tend to be three phases in the treatment of ALL:
Remission Induction Therapy
The goal of remission induction therapy is to destroy leukaemic cells in your child’s blood and bone marrow using cortico-steroids, a combination of chemotherapy drugs and intrathecal chemotherapy. Your child will need to be admitted to hospital during this phase
Almost all children with ALL will achieve a remission following induction therapy. In a small number of cases where this does not occur, a more intensive form of therapy may be recommended by your doctor.
Consolidation Therapy (intensification)
Once the remission induction therapy phase is complete, consolidation therapy treatment is required to help destroy any remaining leukaemia cells. This helps to prevent the disease from reappearing or spreading to the central nervous system in the future, and is administered as blocks of additional chemotherapy drugs and/or steroids over several months.
Maintenance therapy
This phase of treatment helps keep your child’s disease in remission, and may involve chemotherapy tablets taken daily as well as injections of chemotherapy periodically.
The total treatment time for children with ALL tends to be just over two years for girls and just over three years for boys, but your child won’t need to stay in hospital throughout this time.
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Research into ALL
Based at Telethon Kids Institute in WA, Dr Laurence Cheung's current research focus is on understanding leukaemia cells and restoring bone marrow in children with leukaemia.
‘Remarkable improvements have been made to therapy over the past sixty years and modern treatment protocols for children achieve cure rates in more than 90% of patients,’ says Laurence. ‘However, there remain several high-risk genetic subgroups whose outcomes remain poorer, with children from certain groups having less than 40% chance of survival.’
‘Better therapies are desperately needed. My research studies the development of high-risk ALL within the bone marrow and the interaction of leukaemia cells with the neighbouring cells within the bone marrow. By targeting cells surrounding the leukaemia cells, we’re aiming to reduce the impact of cancer and lessen the short- and long-term side effects of traditional treatments for all children diagnosed with ALL.’
Laurence believes that targeting both cancer cells and surrounding cells will result in a more effective therapeutic strategy to treat patients, particularly for children with high-risk leukaemia in which dose-limiting toxicities of conventional chemotherapy has prevented further improvements.
Laurence’s grant is co-funded by Cure Cancer with Cancer Australia and Leukaemia Foundation.
Resources:
Cancer Australia AIHW