Leukemias are cancers of the white blood cells, which occur when the bone marrow creates large numbers of abnormal white blood cells. These abnormal cells can’t do their usual job of fighting infection. They also crowd out the healthy white and red blood cells and platelets in the blood and bone marrow, preventing those cells from performing their normal functions. The result can be infection, anemia (low red blood cell count), and easy bleeding (from a lack of platelets).
How Common Is It?
According to the American Cancer Society, leukemia is the most common type of cancer among children and teens, causing about 30 percent of all childhood cancers. Overall, however, it is considered a rare disease: Only about 2,700 cases of childhood leukemia are diagnosed in the United States each year. Leukemia can develop in children of any age, but the most likely age at diagnosis is between two and ten years. Survival rates for childhood leukemia have improved over time, but many factors influence any one child’s prognosis. Talking with your child’s doctor is the best way to understand how survival statistics apply to your child.
Types of Leukemia
Different types of leukemia are named according to the type of white blood cell that is affected — lymphoid or myeloid. Leukemias are also categorized as acute or chronic, with acute leukemias tending to progress rapidly, and chronic leukemias tending to progress more slowly. Most leukemias that occur in children are acute. The two most common types of leukemia in children are:
Acute lymphoblastic leukemia, or ALL (75 to 85 percent of childhood leukemias)Acute myeloid (or myelogenous) leukemia, or AML (15 to 20 percent)
Less common types of leukemia include:
Chronic myelogenous leukemia, or CML (about 5 percent)Juvenile myelomonocytic leukemia, or JMML (less than 1 percent)
Risk Factors
Most leukemias arise from genetic mutations that occur randomly. That means there is no way to predict or prevent their occurrence. However, there are some things that raise a child’s risk of developing leukemia, including:
Having a sibling with leukemiaBeing exposed to x-rays before birthHaving received chemotherapy or radiation for treatment of cancer in the pastHaving certain genetic conditions, including Down syndromeUse of immunosuppressive drugs following an organ transplant
Signs and Symptoms of Leukemia
In children, signs and symptoms of leukemia may include:
Abdominal pain, caused by an enlarged liver or spleenBone painEasy bruisingFatigueFevers with no apparent causeFrequent infectionsFrequent nosebleeds or bleeding for a long time after a minor cutLimping or refusing to walkNot feeling wellPale skinPoor appetiteSmall spots of blood under the skinSwollen lymph nodes in the neck, groin, or elsewhere
Diagnosis
Diagnosing leukemia usually includes:
A physical exam to look for signs of infection, anemia, and swollen lymph nodes or internal organsA medical history of the child and family membersBlood tests to measure the numbers of white cells, red cells, and platelets in the blood
Depending on the results of the initial exam and blood tests, a child may also need:
A bone marrow biopsyA lymph node biopsyA lumbar puncture to remove a sample of spinal fluidImaging studies such as x-rays or ultrasound
Children who are diagnosed with leukemia are referred to a pediatric hematologist or oncologist for treatment.
Treating Childhood Leukemia
The treatment chosen depends on the type of leukemia a child has as well as his age and initial white blood cell count. Treatment options include:
Chemotherapy (drug therapy), to stop the growth of cancer cellsRadiation, to kill cancer cellsStem cell transplant, using immature blood cells from the blood or bone marrow of a donorTargeted therapy, using drugs that attack cancer cells selectively, sparing normal cells
Treatment often consists of several of the above options in combination to obtain the best outcomes. Follow-up testing is necessary to see how well treatment is working and/or whether the cancer has recurred.
Side Effects
Short-term side effects of chemotherapy for leukemia include hair loss, nausea and vomiting, and increased risk for infection or bleeding. Radiation therapy can cause fatigue, hair loss, and skin dryness or irritation. In children, cancer treatment may also cause late effects that can emerge months to years later. These include:
Increased risk of future cancersInfertilityLasting nerve damageLung, liver, kidney, or heart problems
Even after a child is cancer-free, it’s important that he or she be monitored regularly into adulthood for signs of late-onset side effects.
