Childhood leukemia is a type of leukemia, usually known as acute lymphocytic leukemia (ALL) and a type of childhood cancer. The cure rate of childhood leukemia is generally higher than adult leukemia, approaching 90%, although some side effects of treatment last into adulthood. The older aggressive treatments of cranial irradiation and anthracyclines such as doxorubicin, caused increased risk of solid tumors, heart failure, growth retardation, and cognitive defects.
Leukemia is a hematological malignancy or a cancer of the blood. It develops in the bone marrow, the soft inner part of bones where new blood cells are made. When a child has leukemia, the bone marrow produces white blood cells that do not mature correctly. Normal healthy cells only reproduce when there is enough space for them. The body will regulate the production of cells by sending signals of when to stop production. When a child has leukemia, the cells do not respond to the signals telling them when to stop and when to produce cells, regardless of the available space.
Doctors don’t know exactly what causes most cases of childhood leukemia. But certain factors may increase the chances of getting it. Keep in mind, though, that having a risk factor does not necessarily mean a child will get leukemia. In fact, most children with leukemia don’t have any known risk factors.
The risk for childhood leukemia increases if your child has:
- An inherited disorder such as Li-Fraumeni syndrome, Down syndrome, or Klinefelter syndrome
- An inherited immune system problem such as ataxia telangiectasia
- A brother or sister with leukemia, especially an identical twin
- A history of being exposed to high levels of radiation, chemotherapy, or chemicals such as benzene (a solvent)
- A history of immune system suppression, such as for an organ transplant
Although the risk is small, doctors advise that children with known risk factors have regular checkups to spot any problems early.
Signs and Symptoms
As leukemia cells build up in the bone marrow, they can crowd out the normal blood cell-making cells. As a result, a child may not have enough normal red blood cells, white blood cells, and blood platelets. These shortages show up on blood tests, but they can also cause symptoms. The leukemia cells may also invade other areas of the body, which can also cause symptoms.
Many of these symptoms have other causes as well, and most often they are not from leukemia. Still, it’s important to let your child’s doctor know about them right away so that the cause can be found and treated, if needed.
- Fatigue (tiredness), pale skin: Anemia (a shortage of red blood cells) might make a child feel tired, weak, lightheaded, or short of breath. It may also cause pale skin.
- Infections and fever: A child with leukemia may develop fever. This is often caused by an infection, which may not improve even with antibiotics. This is because of a lack of normal white blood cells, which would normally help fight the infection. Although children with leukemia may have very high white blood cell counts, the leukemia cells do not protect against infection the way normal white blood cells do. Fever is also sometimes caused by the leukemia cells themselves releasing certain chemicals into the body.
- Easy bleeding or bruising: A child with leukemia may bruise easily, have frequent nosebleeds and bleeding gums, or bleed too much from small cuts. There may be pinhead-sized red spots on the skin caused by bleeding from tiny blood vessels. This comes from a lack of blood platelets, which normally stop bleeding by plugging holes in damaged blood vessels.
- Bone or joint pain: Some children with leukemia will have bone pain or joint pain. This is from the buildup of leukemia cells near the surface of the bone or inside the joint.
- Swelling of the abdomen (belly): Leukemia cells may collect in the liver and spleen, causing them to enlarge. This may be noticed as a fullness or swelling of the belly. The lower ribs usually cover these organs, but when they are enlarged the doctor can often feel them.
- Loss of appetite, weight loss: If the spleen and/or liver become large enough, they may press against other organs like the stomach. This can limit the amount of food that can be eaten, leading to a loss of appetite and weight loss over time.
- Swollen lymph nodes: Some leukemias spread to lymph nodes. The child, a parent, or a health professional may notice swollen nodes as lumps under the skin in certain areas of the body (such as on the sides of the neck, in underarm areas, above the collarbone, or in the groin). Lymph nodes inside the chest or abdomen may also swell, but these can only be detected by imaging tests, such as CT or MRI scans. Lymph nodes often enlarge when they are fighting an infection, especially in infants and children. An enlarged lymph node in a child is more often a sign of infection than leukemia, but it should be checked by a doctor and followed closely.
- Coughing or trouble breathing: The T-cell type of acute lymphocytic leukemia (ALL) often affects the thymus, which is a small organ in the chest behind the breastbone (sternum) and in front of the windpipe (trachea). An enlarged thymus or lymph nodes inside the chest can press on the trachea. This can lead to coughing or trouble breathing.
- Swelling of the face and arms: The superior vena cava (SVC), a large vein that carries blood from the head and arms back to the heart, passes next to the thymus. Growth of the thymus from the buildup of leukemia cells may press on the SVC, causing the blood to “back up” in the veins. This is known as SVC syndrome. It can cause swelling in the face, neck, arms, and upper chest (sometimes with a bluish-red skin color). It can also cause headaches, dizziness, and a change in consciousness if it affects the brain. The SVC syndrome can be life-threatening, and needs to be treated right away.
- Headache, seizures, vomiting: A small number of children have leukemia that has already spread to the central nervous system (brain and spinal cord) when they are first diagnosed. Headache, trouble concentrating, weakness, seizures, vomiting, problems with balance, and blurred vision can be symptoms of spread to the central nervous system.
- Rashes, gum problems: In children with acute myelogenous leukemia (AML), leukemia cells may spread to the gums, causing swelling, pain, and bleeding. If it has spread to the skin, it can cause small, darkly colored spots that look like common rashes. A collection of AML cells under the skin or in other parts of the body is called a chloroma or granulocytic sarcoma.
- Extreme fatigue, weakness: One rare but very serious consequence of AML is extreme tiredness, weakness, and slurring of speech. This can occur when very high numbers of leukemia cells cause the blood to become too thick and slow the circulation through small blood vessels of the brain.
To diagnose childhood leukemia, the doctor will take a thorough medical history and perform a physical exam. Tests are used to diagnose childhood leukemia as well as classify its type.
Initial tests may include:
- Blood tests to measure the number of blood cells and see how they appear.
- Bone marrow aspiration and biopsy, usually taken from the pelvic bone, to confirm a diagnosis of leukemia.
- Lumbar puncture, or spinal tap, to check for spread of leukemia cells in the fluid that bathes the brain and spinal cord.
A pathologist examines cells from the blood tests under a microscope. This specialist also checks bone marrow samples for the number of blood-forming cells and fat cells.
Other tests may be done to help determine which type of leukemia your child may have. These tests also help the doctors know how likely the leukemia is to respond to treatment.
Certain tests may be repeated later to see how your child responds to treatment.
The treatment a child will undergo is based on the child’s age, overall health, medical history, their tolerance for certain medications, procedures, and therapies, along with the parents’ opinion and preference.
- Chemotherapy is a treatment that uses drugs to interfere with the cancer cells ability to grow and reproduce. Chemotherapy can be used alone or in combination with other therapies. Chemotherapy can be given either as a pill to swallow orally, an injection into the fat or muscle, through an IV directly into the bloodstream, or directly into the spinal column.
- A stem cell transplant is a process by which healthy cells are infused into the body. A stem-cell transplant can help the human body make enough healthy white blood cells, red blood cells, or platelets, and reduce the risk of life-threatening infections, anemia, and bleeding. It is also known as a bone-marrow transplant or an umbilical-cord blood transplant, depending on the source of the stem cells. Stem cell transplants can use the cells from the same person, called an autologous stem cell transplant or they can use stem cells from other people, known as an allogenic stem cell transplant. In some cases, the parents of a child with childhood leukemia may conceive a saviour sibling by preimplantation genetic diagnosis to be an appropriate match for the HLA antigen.
- Targeted therapy is also sometimes used for leukemia. This therapy targets specific parts of cancer cells, working differently than standard chemotherapy. Effective for certain types of childhood leukemia, targeted therapy often has less severe side effects.
- Radiation therapy, which uses high-energy radiation to kill cancer cells and shrink tumors. It may be used to help prevent or treat the spread of leukemia to other parts of the body. Surgery is rarely used to treat childhood leukemia.