Childhood Lymphocytic Leukaemia
Contents:
General
Leukaemia is a cancer of the blood-forming cells, most commonly white blood cells. Leukaemia starts in the bone marrow, from there it can spread to the blood, lymph nodes, spleen, liver, central nervous system, and other organs. Both children and adults can develop leukaemia, however leukaemia is the most common child hood cancer.
Types of Leukaemia
Leukaemia can be either acute (rapidly growing) or chronic (slower growing). Almost all leukaemia in children is acute. Acute leukaemia is divided into 2 types:
1. acute myelogenous leukaemia (referred to as AML)
For information on Childhood Acute Myelogenous leukaemia (AML) please see relevant fact sheet.
2. acute lymphocytic leukaemia (referred to as ALL)
Childhood Acute lymphocytic leukaemia is the most common type of cancer in children. The cancer develops from lymphocytes (a type of white blood cell) in the bone marrow. Too many lymphocytes are produced and they are unable to fight infection very well. As the number of lymphocytes increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anaemia, and bleeding.
ALL is divided into different groups based on the cell type (B-cell or T-cell) that is affected, how developed the cancer cells are and how different they are from normal cells. About 85% of cases of Acute lymphocytic leukaemia are of the B-cell type. And within this group, there are several subtypes as well.
Risk Factors
For the most part, lifestyle risk factors such as diet and exercise, are not linked to childhood cancers.
Race
Whites and Hispanics are more likely to develop ALL.
Genetics/family history
Having a brother or sister with ALL increases the risk of developing the disease.
Genetic disorders
Certain genetic diseases that cause children to be born with an abnormal immune system increase their risk of developing ALL. Conditions such as Li-Fraumeni syndrome, Down's syndrome, Klinefelter's syndrome and others carry an increased risk of leukaemia.
Chemotherapy
Past treatment with chemotherapy or other drugs that weaken the immune system can slightly increase the risk of ALL.
Radiation
Exposure to radiation and a history of aplastic anaemia may affect the risk of developing childhood ALL. Being exposed to ionizing radiation or chemicals such as benzene may also increase the risk.
X-rays
Being exposed to x-rays before birth is thought to increase the risk
Prevention
At the moment scientists do not know how to prevent most cases of leukaemia.
Children with a higher risk of leukaemia, children who have been treated with chemotherapy or radiation therapy for an earlier cancer, children who have certain genetic conditions, and children who have received organ transplants should have close follow-ups by their doctor.
Screening
At this time, there are no special tests to help find leukaemia early.
Symptoms
Possible signs of childhood ALL include fever, feeling tired, and bleeding or bruising easily. Most of the signs and symptoms of leukaemia result from the crowding out of normal blood cells in the bone marrow by leukaemia cells.
Fatigue, loss of appetite or pale skin
A child may complain of shortness of breath or of being very tired. The child's skin may be pale because of the shortage of red blood cells. There may also be a loss of appetite.
Extreme tiredness and weakness
One unusual but very serious symptom of ALL is extreme tiredness, weakness, and slurring of speech. This can happen when very high numbers of cancer cells make the blood too thick and reduce the flow of blood to the brain.
Infection
A child with leukaemia may get an infection that doesn't respond to antibiotics, have a high fever, and become very sick. This can happen because there are not enough normal white blood cells. Although children with leukaemia often have very high white blood cell counts, the cells are not normal and do not protect against infection very well.
Easy bleeding or bruising
A child with leukaemia may bruise easily or have increased bleeding from small cuts and nosebleeds. There may be small red spots on the skin from bleeding from tiny blood vessels known as petechiae. The bleeding is caused by a lack of blood platelets, which are needed for plugging holes in blood vessels.
Bone pain
Some children will have bone pain, and a smaller number will have joint pain. Leukaemia cells can collect underneath the covering of the surface of the bone or inside the joint.
Swelling and painless lumps
ALL can cause the liver or spleen to get larger. There may also Painless lumps in the neck, underarm, stomach, or groin.
Swollen lymph nodes
ALL can spread to lymph nodes causing them to swell. The child, a parent, or a doctor or nurse might notice swollen nodes on the sides of the neck, in the groin, in the underarm area, or above the collarbone.
Swelling of the thymus
The T-cell type of ALL often involves the thymus gland, a gland found in the centre of the chest, near the heart. An enlarged thymus can press on the nearby windpipe, causing coughing, shortness of breath, or even suffocation. A large vein that carries blood from the head and arms back to the heart passes next to the thymus. If leukaemia cells compress the large vein, swelling of the head and arms (called SVC syndrome) can result. This can affect the brain and is life threatening.
Headache, seizures, vomiting
Leukaemia cells can spread outside the bone marrow into the central nervous system, causing headaches and a number of other symptoms.
Rashes, gum problems
Cancer cells can spread to the gums, causing swelling, pain, and bleeding. Spread to the skin can cause spots that look like rashes.
Diagnosis
Tests that examine the blood and bone marrow are used to detect and diagnose ALL.
The following tests may be used:
Blood cell counts and other blood tests
Most children with leukaemia will have either too many white cells in their blood and not enough red blood cells or platelets. Also, the white blood cells will be "young" cells normally found in the bone marrow but not in the blood.
A Complete blood count will test
- The number of red blood cells, white blood cells, and platelets.
- The amount of haemoglobin (the protein that carries oxygen) in the red blood cells.
- The portion of the sample made up of red blood cells.
- Other blood tests will be done to measure certain chemicals in the blood to tell how well the liver and kidneys are working.
Cytogenetic analysis
A test in which the cells in a sample of blood or bone marrow are looked at under a microscope to find out if there are certain changes in the chromosomes in the lymphocytes. For example, in some leukaemia, part of one chromosome is moved to another chromosome. This is called the 'Philadelphia chromosome'.
Immunophenotyping
The cells in a sample of blood or bone marrow are looked at under a microscope to find out if the cancer began from the B lymphocytes or the T lymphocytes. The test can be used to determine the subtype of AML.
Bone marrow biopsy and aspiration
A small piece of bone and bone marrow is removed by inserting a needle into the hipbone or breastbone. A pathologist views the bone and bone marrow samples under a microscope to look for signs of cancer. This test can also be used later to see if the leukaemia is responding to treatment.
Spinal tap (lumbar puncture)
A small needle is placed between the bones in the child's spine in the lower back to draw out some cerebrospinal fluid (CSF). The fluid is looked at for leukaemia cells. A lumbar puncture can also be used to deliver chemotherapy drugs directly into the spinal fluid to prevent the cancer from spreading to the spinal cord and brain.
Lymph node biopsy
An entire lymph node is removed to examine. If the node is near the skin's surface, this is a simple operation that can be done by numbing just the area around the node. But if the node is inside the chest or abdomen, the child will need general anaesthetic.
X-ray
An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. Can be used to see if there is a mass in the chest or leukaemia in the bones or the joints.
Ultrasound
Uses sound waves to produce images of internal organs. This test can distinguish solid from fluid-filled masses. Ultrasound can be used to help show if there is leukaemia in the kidney, spleen, or liver.
CT scan (computed tomography)
A kind of x-ray in which a beam moves around the body, taking pictures from different angles. CT scans are not often used in leukaemia, but they can show if there is disease in the lymph nodes of the chest or in back of the abdomen.
MRI (magnetic resonance imaging)
Powerful magnets and radio waves are used to produce detailed, computer-generated pictures of the body. This scan might be used when there is concern about leukaemia invading the brain.
Gallium Scan and Bone Scan
A radioactive chemical is injected which then collects in areas of cancer or infection. These tests can help to detect infection or cancer in the bones.
Treatment
The treatment options depend on the type of leukaemia. Chemotherapy is the main treatment for nearly all types of ALL. Unlike most other cancers, surgery rarely has any role in the treatment of leukaemia. This is because leukaemia is a disease of blood and bone marrow and cannot be cured with surgery.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. The way the chemotherapy is given depends on the type of cancer being treated. ALL will involve the use of lower doses of drugs over a longer period of time.
Side effects of chemotherapy
While chemotherapy drugs kill cancer cells, they can also damage normal cells. This happens because they target cells that are growing quickly such as cancer cells. But in the process they also damage other fast-growing cells. The lining of the mouth and intestines, hair, and blood cells all grow quickly and are likely to be damaged by chemotherapy.
As a result, children being treated with chemotherapy may have a higher risk of infection (from low white blood cell counts), may bruise or bleed easily (from low blood platelets), and tire easily (from low red blood cell counts). Other side effects of chemotherapy can include temporary hair loss, nausea, vomiting, diarrhoea, mouth sores, and loss of appetite.
These side effects usually go away shortly after treatment ends. And there are often ways to manage these side effects during treatment.
Tumour lysis syndrome is a side effect of chemotherapy caused by the rapid breakdown of leukaemia cells. When these cells die, they release substances into the bloodstream that can affect the kidneys, heart, and nervous system. Giving the child extra fluids or certain drugs that help rid the body of these toxins can prevent this problem.
Organs that could be damaged by chemotherapy include the kidneys, liver, testes, ovaries, brain, heart, and lungs. With careful monitoring, such side effects are rare.
Radiation Therapy
For children with acute leukaemia, radiation might be used to treat cancer that has spread to the central nervous system or testicles. It can also be used, though rarely, in an emergency to treat pressure on the windpipe.
Bone Marrow or Peripheral Blood Stem Cell Transplantation (SCT)
This treatment can be used for children whose chances of survival are very poor with standard or even intensive chemotherapy. It can be done as soon as the cancer is in remission or when the child has a relapse during or shortly after treatment. It is not clear how useful it is for children whose relapse happens more than 6 months after the end of their first treatment.
Chemotherapy can harm normal cells as well as cancer cells. Stem cell transplantation offers a way for doctors to use the high doses of chemotherapy needed for effective treatment. Although the drugs destroy the bone marrow, transplanted stem cells can restore the blood-producing bone marrow stem cells.
Stem cells for transplantation are collected from the bone marrow or from the bloodstream (in a process called aphaeresis). These stem cells can come from either the child or from a matched donor such as a brother or sister. Stored cells from umbilical cord blood have also been used for unrelated donor transplants.
The child is given very high doses of chemotherapy (and sometimes radiation) to kill the cancer cells. After treatment, the stored stem cells are given to the child as a blood transfusion. Then the waiting period begins as the stem cells settle in the child's bone marrow and start to grow and produce blood cells.
Side effects of radiation therapy
Stem cell transplantation is a complex treatment and requires a lengthy hospital stay.
Other drug therapy
Arsenic trioxide and all-trans retinoic acid (ATRA) are anticancer drugs that kill leukaemia cells, stop the leukaemia cells from dividing, or help the leukaemia cells mature into white blood cells. These drugs are used in the treatment of a subtype of AML called acute promyelocytic leukaemia.
Biologic therapy
This treatment is currently being tested in clinical trials. Biologic therapy is a cancer treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defences against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.
Monoclonal antibody
This is a type of biologic therapy also at the trial stage. Monoclonal antibody therapy is a cancer treatment that uses antibodies made in the laboratory, from a single type of immune system cell. These antibodies can identify substances on cancer cells or normal substances that may help cancer cells grow. The antibodies attach to the substances and kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to deliver drugs, toxins, or radioactive material directly to cancer cells.
Statistics
World
- World-wide over 250,000 people are diagnosed with Leukaemia each year.
- Leukaemia accounts for 2.5% of all cancers
- Generally rates are higher in Caucasian populations
- ALL is uncommon in Africa
Europe
- There are approximately 66,000 new cases of Leukaemia in Europe each year.
- 2.4% of cases are attributable to occupational exposure.
- Across Europe there appears to be more variation in rates for males than in females.
- The highest male death rate is in Luxembourg almost twice as high as that in the Netherlands.
- The highest female death rate is also in Luxembourg and is less than 50% higher than the lowest rate in Austria.
UK
- Leukaemias represent 2.5 % of all cancers in the UK
- There are approximately 6,600 new cases diagnosed in the UK each year
- ALL is the most common cancer in children with 370 new cases each year in the UK.
- This accounts for around ¾ of all childhood leukaemias
- ALL is the most common leukaemia in people under 20, accounting for over 70% of all cases.
Trends
- In Europe there was a 10% decrease in mortality for leukaemia between 1988 and 1997. This is partly because of advances in treatment.
- It is thought the decline represents 7,000 deaths a year that have been avoided.
- Incidence rates in Britain for all leukaemias combined have increased slowly. This could be because of better diagnostic tools and registration of cancers.
- In Britain rates of ALL are stable or decreasing.
Socio economic
In England and Wales incidence rates of leukaemia are marginally higher in more affluent groups.
Survival
There has been dramatic improvement in the survival of children with leukaemia because of advances in treatment and more specialist care.
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