Leukemia – Childhood
About the Disease
Leukemia is the most common childhood cancer. It begins in the bone marrow but can spread to the blood, lymph nodes, spleen, liver, brain and other organs.
White cells in the blood protect the body from infection and disease. In cases of acute leukemia, the cells are released into the bloodstream before they mature, reproducing rapidly. Chronic leukemia is rare in children and occurs when the cells are more mature and don’t reproduce as quickly. Two kinds of white cells can be affected: the lymphocytes and granulocytes. So the types of leukemia are:
Acute Lymphoblastic Leukemia (ALL) is the most common, making up almost three quarters of all cases. It occurs when the body is producing too many lymphocytes, affecting the body’s ability to fight infection and crowding out healthy cells. This disease affects children under three years of age and young teens.
Acute Myelogenous Leukemia (AML) can affect both children and adults and makes up about 20 per cent of all childhood leukemias. It occurs when the body produces too many granulocytes, crowding out healthy cells.
Juvenile Myelomonocytic Leukemia (JMML) is rare and affects only children under four years of age.
About 35 Alberta children under the age of 14 are diagnosed with leukemia every year.
Risk Factors
Risk factors are determined by analyzing the numbers of patients with cancer in a larger population and trying to find differences in the characteristics or behaviors between those individuals who develop cancer and those who do not. The Tomorrow Project, for instance, is tracking more than 50,000 Albertans over a fifty-year period to learn more about who develops cancer and why.
Other factors that may increase the risk of developing childhood leukemia include:
- Exposure to radiation
- Exposure to x-rays before birth
- Previous chemotherapy treatment
- Genetic disorders, such as Down Syndrome, Fanconi’s Anemia, or Noonan’s Syndrome
- Race – more common among whites and Hispanics
- Exposure to cigarette smoke or alcohol before birth
- Exposure to ionizing radiation or chemicals such as benzene
Factors that may decrease the risk of developing childhood leukemia include:
- Non-smoking mother during pregnancy
- Non-drinking mother during pregnancy
Genetic Link
The risk of childhood leukemia is higher if a sibling has been diagnosed with the disease, and especially if that sibling is a twin.
Detection and Diagnosis
Leukemia symptoms can often be initially confused with those of the flu. The child is often feverish, tired and weak. There may be an unexplained weight loss, frequent infections, bone or joint pain and swollen or tender lymph nodes. There is often a fever and the child may suffer from night sweats. Tiny red spots could appear under the skin.
Initial tests could include a blood count to check for the numbers of white and red blood cells and platelets.
The only way to confirm a leukemia diagnosis is through a biopsy. This involves taking a sample of bone marrow, usually from the hip, with a needle. A spinal tap will be needed to see if the disease has spread to the central nervous system.
Treatment
Treatment options for childhood leukemia include chemotherapy and radiation therapy, often in combination depending on the progression of the disease.
Chemotherapy is the most common treatment for childhood leukemia. It involves using drugs to kills the cancer cells or to stop them from dividing. The treatment can be either oral or injection.
Bone Marrow Transplants may be needed for those children who don’t respond to standard treatment or for those whose leukemia has reoccurred. Stems cells can be taken from the patient before treatment and then reinfused (autologous) or taken from a donor whose marrow is a close match (allogeneic). The treatment is aimed at replacing diseased stem cells with healthy ones that will in turn produce healthy white cells.
Radiation therapy, concentrated beams of high-energy X-rays, is sometimes used alone or in combination with chemotherapy, usually when the leukemia has affected the brain and central nervous system. Internal radiation involves sealing a radioactive substance in needles, seeds or wires that are placed directly near the cancer.
Factors Affecting Prognosis
The chances of recovery depend on the white cell count at diagnosis and whether there are chromosomal changes in the leukemia cells. Most children with Down Syndrome can be cured of their leukemia.
Children can experience “late effects” from treatment long after it ends. Radiation can affect the development of the brain and may cause second cancers, especially brain tumours.
