Childhood leukemia

Childhood leukemia is a type of leukemia, usually acute lymphocytic leukemia (ALL), that affects children. The cure rate of childhood leukemia is generally higher than adult leukemia, approaching 90%, although the 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.^[1]

Leukemia is cancer of the blood and 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.

Types

Leukemia is usually described either as "acute", which grows quickly, or "chronic", which grows slowly. One main type of acute leukemia is acute lymphocytic leukemia (ALL), which accounts for about 3 out of 4 cases of leukemia in children. ALL is a form of leukemia that affects the lymphocytes, a type of white blood cells which fights infection. When a patient has ALL, the bone marrow makes too many immature white blood cells and they do not mature correctly. Therefore, the white blood cells over-produce, crowding the other blood cells. The white blood cells also do not work correctly to fight infection.

Another type of acute leukemia is acute myelogenous leukemia (AML). AML is cancer of the blood in which too many myeloblasts, immature white blood cells, are produced in the bone marrow. The marrow continues to produce abnormal cells that crowd the other blood cells and do not work properly to fight infection. Almost all childhood leukemia is acute.

Chronic leukemias are more common in adults, than in children, and although they tend to grow more slowly than acute leukemias, they are harder to treat. These chronic leukemias are divided into two types: chronic myelogenous leukemia (CML) and chronic lymphocytic leukemia (CLL). CML is rare in children, but does occur and is treatable in children the same as in adults. CML patients have too many immature white blood cells being produced, and the cells crowd the other healthy blood cells.

A specific chromosome rearrangement is also found in patients with CML, among the 46 chromosomes in human cells. Part of chromosome nine breaks off and attaches itself to chromosome 22, meaning there is an exchange of genetic material between chromosomes 9 and 22. The rearrangement of the chromosomes changes the positions and functions of certain genes, which causes uncontrolled cell growth.

CLL is another form of chronic leukemia, but is extremely rare in children. Juvenile myelomonocytic leukemia (JMML) is a form of leukemia that is neither chronic nor acute and occurs most often in children under the age of four. JMML begins from myeloid cells, but is not as fast-growing as AML or as slow as CML.

Causes

Most childhood leukemias are acquired genetic diseases. The immune system plays an important role in protecting the body's immune system. An alteration or defect in the immune system may increase the risk for developing cancer. The immune system can be damaged by different factors, such as exposure to different viruses, environmental factors, chemical factors and other various infections.

Symptoms

Most initial symptoms of leukemia are similar to symptoms for irregular bone-marrow function. Typically, most symptoms do not occur during the early stages of leukemia, and children may experience different symptoms. The following are symptoms of leukemia that lead doctors to look for different types of juvenile leukemia:

• feelings of fatigue
• repetitive viral or bacterial infections
• bone and joint pain
• abdominal pain which may cause loss of appetite and weight loss in a child
• swollen lymph nodes under the arms, in the groin, chest and neck.

Diagnosis

Leukemia is diagnosed in a variety of ways. Some diagnostic procedures include:

• A bone-marrow aspiration and biopsy; marrow may be removed by aspiration or a needle biopsy.
• A complete blood count, which is a measurement of size, number, and maturity of different blood cells in blood.
• Blood tests may include blood chemistry, evaluation of liver and kidney functions, and genetic studies.
• A lymph-node biopsy; lymph node tissue is surgically removed to examine under a microscope, to look for cancerous cells.
• A spinal tap: a special needle is placed into the lower back into the spinal canal, which is the area around the spinal cord. Cerebral spinal fluid is fluid that bathes the child's brain and spinal cord. A small amount of cerebral spinal fluid is sent for testing to determine if leukemia cells are present.

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 your body, called an autologous stem cell transplant or they can use stem cells from donors known as a allogenic stem cell transplant.

Emotional after-effects

Childhood leukemia is a very taxing disease, on the caregiver and the child. The emotional distress and post traumatic stress which it causes is very deep; studies show that only 3% of parents have to deal with their child becoming severely ill. It is common to experience stress, depression, and anxiety throughout and after cancer treatment. Many people find it helpful to talk about their feelings with family and friends, health professionals, other patients, members of the clergy, and counsellors or therapists. Being part of a support group can provide another outlet for people to share their feelings. Relaxation techniques, such as guided imagery and slow rhythmic breathing, can also help to ease negative thoughts or feelings. Reaching out to others, by participating in volunteer activities, can help people to feel stronger and more in control. However, people who continue to experience emotional distress should ask their doctor to refer them to someone who can help determine what may be causing or contributing to their distress and how to deal with it.

References

1. ^ New England Journal of Medicine, 365(15):1417, Adult primary care after childhood acute lymphoblastic leukemia

Sources

• "Chronic Myelogenous Leukemia." Disease Information. 13 November 2009. The Leukemia and Lymphoma Society. 17 November 2009 <www. lls.org>.
• "Juvenile Myelomonocytic Leukemia." My Child Has. 2006. Children's Hospital Boston. 17 November 2009 <www. childrenshospital.org>.
• "What is Childhood Leukemia?." Cancer Reference Information. 14 May 2009. American Cancer Society. 17 November 2009 <www.cancer.org>.
• "What are the Differences Between Cancer in Adults and Children?." Cancer Reference Information. 14 May 2009. American Cancer Society. 17 November 2009 <www.cancer.org>.
• Pöder, U., Ljungman, G., & von Essen, L. (2008). Posttraumatic stress disorder among parents of children on cancer treatment: a longitudinal study. Psycho-Oncology, 17(5), 430-437. doi:10.1002/pon.1263