What is the main cause of childhood leukemia?
Also:
How does it happen?
Treatments?
Etc?
anything you know will help!!
- Danny 852
So many types of leukemia which type do you want to know about?
Acute myeloid leukemia (Subtype M0-M7)
Acute lymphoblastic leukemia
Chronic myeloid leukemia
Chronic Lymphocytic leukemia
Hairy Cell leukemia
etc.
For children most common would be Acute Lymphoblastic Anemia (ALL), but they can have other types too.
For ALL, factors like certain genetic diseases, family history, radiation (Chernobyl), chemicals have been linked to it. But most children having it are not having any known predisposing factors. So wt causes it is still a mystery.
For treatment, generally it's like Chemo, Radiotherapy, Bone marrow transplant, and of course Supportive Rx. For details u hv to read abt it. different subtypes of ALL got different treatment. It would be a whole page.
Hope this helps :)
- cindy
Childhood Leukemia
What is leukemia?
Leukemia is cancer of the blood and develops in the bone marrow. The bone marrow is the soft, spongy center of the long bones that produces the three major blood cells: white blood cells to fight infection; red blood cells that carry oxygen; and platelets that help with blood clotting and stop bleeding. When a child has leukemia, the bone marrow, for an unknown reason, begins to make white blood cells that do not mature correctly, but continue to reproduce themselves. Normal, healthy cells only reproduce when there is enough space for them to fit. The body can regulate the production of cells by sending signals when to stop. With leukemia, these cells do not respond to the signals to stop and reproduce, regardless of space available.
These abnormal cells reproduce very quickly and do not function as healthy white blood cells to help fight infection. When the immature white blood cells, called blasts, begin to crowd out other healthy cells in the bone marrow, the child experiences the symptoms of leukemia (i.e., infections, anemia, bleeding).
Who is affected by leukemia?
Leukemia is the most common form of cancer in childhood. It affects approximately 3,000 children each year in the US, accounting for about 30 percent of childhood cancers.
Leukemia can occur at any age, although it is most commonly seen in children between 2 and 6 years of age. The disease occurs slightly more frequently in males than in females, and is more commonly seen in Caucasian children than in African-American children, or children of other races.
What causes leukemia in children?
The majority of childhood leukemias are acquired genetic diseases. This means that gene mutations and chromosome abnormalities in cells occur sporadically (by chance).
The immune system plays an important role in protecting the body from diseases and possibly cancer. An alteration or defect in the immune system may increase the risk for developing leukemia. Factors such as exposure to certain viruses, environmental factors, chemical exposures and various infections have been associated with damage to the immune system.
With the exception of specific genetic syndromes, little is known about the causes of childhood leukemia.
What are the different types of leukemia?
There are three main types of leukemia, including the following:
Acute lymphocytic leukemia (ALL) - Acute lymphocytic leukemia (ALL), also called lymphoblastic or lymphoid, accounts for about 75 to 80 percent of the childhood leukemias. In this form of the disease, the lymphocyte cell line is affected. The lymphocytes normally fight infection. With acute lymphocytic leukemia, the bone marrow makes too many of these lymphocytes and they do not mature correctly. The lymphocytes overproduce, thus, crowding out other blood cells. Immature blood cells (blasts) do not work properly to fight infection. Acute leukemia can occur over a short period of days to weeks. Chromosome abnormalities (extra chromosomes and structural changes in the chromosome material) are present in the majority of ALL patients.
Acute myelogenous leukemia (AML) - Acute myelogenous leukemia (AML), also called granulocytic, myelocytic, myeloblastic, or myeloid, accounts for about 20 percent of the childhood leukemias. Acute myelogenous leukemia is a cancer of the blood in which too many granulocytes, a type of white blood cell, are produced in the marrow. The granulocytes normally fight infection. With acute myelogenous leukemia, the bone marrow makes too many of these cells and they do not mature correctly. The granulocytes overproduce, thus, crowding out other blood cells. Immature blood cells (blasts) do not work properly to fight infection. Acute leukemia can occur over a short period of days to weeks. Children with certain genetic syndromes, including Fanconi anemia, Bloom syndrome, Kostmann syndrome, and Down syndrome, are at a higher risk of developing AML than other children.
Chronic myeloblastic leukemia (CML) - Chronic myeloblastic leukemia (CML) is uncommon in children. Chronic myeloblastic leukemia is cancer of the blood in which too many granulocytes, a type of white blood cell, are produced in the marrow. The granulocytes normally fight infection. With this disease, the bone marrow makes too many of these cells and they do not mature correctly. The marrow continues to produce these abnormal cells which crowd out other healthy blood cells. Chronic myeloblastic leukemia can occur over a period of months or years. A specific chromosome rearrangement is found in patients with CML. Part of chromosome #9 breaks off and attaches itself to chromosome #22, so that there is an exchange of genetic material between these two chromosomes. This rearrangement changes the position and functions of certain genes, which results in uncontrolled cell growth. Other chromosome abnormalities can also be present.
The difference between lymphocytic and myelogenous is the stage of development on what is called the pluripotent stem cell. The pluripotent stem cell is the first stage of development of all of the blood cells (white blood cells, red blood cells, and platelets). This stem cell goes through stages of development until it matures into a functioning cell. The type of leukemia is determined by where the cell is in the stage of development when it becomes malignant, or cancerous.
The stem cell matures into either the lymphoid or myeloid cells. The lymphoid cells mature into either B-lymphocytes or T-lymphocytes. If the leukemia is among these cells, it is called acute lymphocytic leukemia (ALL). If the leukemia is found even further along this stage of development, it can be further classified as B-cell ALL or T-cell ALL. The more mature the cell, the more difficult it is to treat.
The myeloid cells develop into platelets, red blood cells, and specialized white blood cells called neutrophils and macrophages. There are many classifications of AML. The type of leukemia is determined by the stage of development when the normal cells become leukemia cells.
What are the symptoms of leukemia?
Because leukemia is cancer of the blood-forming tissue called the bone marrow, the initial symptoms are often related to irregular bone marrow function. The bone marrow is responsible for storing and producing about 95 percent of the body's blood cells, including the red blood cells, white blood cells and platelets.
When leukemia occurs, the abnormal white blood cells (blasts) begin to reproduce very rapidly and begin crowding out and competing for nutrients and space with the other healthy cells. The following are the most common symptoms of leukemia. However, each child may experience symptoms differently. Symptoms may include:
Anemia - When red blood cells are unable to be produced because of the crowding in the marrow, anemia is present. With anemia, the child may appear tired, pale and may breathe faster to compensate for the decrease in oxygen carrying capacity. The number of red blood cells on a blood count will be below normal.
Bleeding and/or bruising - When platelets are unable to be produced because of the crowding in the marrow, bleeding can occur and the child may begin to bruise more easily. Petechia are tiny red dots often seen on the skin of a child with low number of platelets. Petechia are very small blood vessels that have "leaked" or bled. The number of platelets on a blood count will be below normal. Thrombocytopenia is the term used for a decreased number of platelets.
Recurrent infections - Although there may be an unusually high number of white blood cells on a blood count of a child with leukemia, these white blood cells are immature and do not fight infection. The child may have had repetitive viral or bacterial infections over the past few weeks. The child with leukemia often shows symptoms of an infection such as fever, runny nose and cough.
Bone and joint pain - Pain in bones and joints is another common symptom of leukemia. This pain is usually a result of the bone marrow being overcrowded and "full."
Abdominal distress - Abdominal pain may also be a symptom of leukemia. Leukemia cells can collect in the kidney, liver, and spleen, causing enlargement of these organs. Pain in the abdomen may cause a child to have loss of appetite and weight loss.
Swollen lymph nodes - The child may also have swelling in the lymph nodes under the arms, in the groin, chest and in the neck. Lymph nodes are responsible for filtering the blood. Leukemia cells may collect in the nodes, causing swelling.
Difficulty breathing (dyspnea) - With T-cell ALL, these leukemia cells tend to clump together around the thymus. This mass of cells present in the middle of the chest can cause pain and difficulty breathing (dyspnea). Wheezing, coughing, and/or painful breathing requires immediate medical attention.
With acute leukemia (ALL or AML), these symptoms may occur suddenly in a matter of days or weeks. With chronic leukemia (CML), these symptoms may develop slowly over months to years.
It is important to understand that the symptoms of leukemia may resemble other blood disorders or medical problems. These are common symptoms of the disease, but do not include all possible symptoms. Children may experience symptoms differently. Always consult your child's physician for a diagnosis.
How is leukemia diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for leukemia may include:
Bone marrow aspiration and biopsy - marrow may be removed by aspiration or a needle biopsy under local anesthesia. In aspiration biopsy, a fluid specimen is removed from the bone marrow. In a needle biopsy, marrow cells (not fluid) are removed. These methods are often used together.
Complete blood count (CBC) - a measu
- Ely
Acute lymphoblastic leukemia (ALL), also known as acute lymphocytic leukemia, is a form of leukemia, or cancer of the white blood cells.
Malignant, immature white blood cells continuously multiply and are overproduced in the bone marrow. ALL causes damage and death by crowding out normal cells in the bone marrow, and by spreading (metastasizing) to other organs. ALL is most common in childhood and young adulthood with a peak incidence at 4-5 years of age, and another peak in old age. The overall cure rate in children is 85%, and about 50% of adults have long-term disease-free survival.[1] 'Acute' refers to the undifferentiated, immature state of the circulating lymphocytes ("blasts"), and to the rapid progression of disease, which can be fatal in weeks to months if left untreated.
Symptoms
Initial symptoms are not specific to ALL, but worsen to the point that medical help is sought. The signs and symptoms of ALL are variable but follow from bone marrow replacement and / or organ infiltration.
Generalised weakness and fatigue
Anemia
Frequent or unexplained fever and infections
Weight loss and/or loss of appetite
Excessive and unexplained bruising
Bone pain, joint pains (caused by the spread of "blast" cells to the surface of the bone or into the joint from the marrow cavity)
Breathlessness
Enlarged lymph nodes, liver and/or spleen
The signs and symptoms of ALL result from the lack of normal and healthy blood cells because they are crowded out by malignant and immature leukocytes (white blood cells). Therefore, people with ALL experience symptoms from malfunctioning of their erythrocytes (red blood cells), leukocytes, and platelets not functioning properly. Laboratory tests which might show abnormalities include blood count tests, renal function tests, electrolyte tests and liver enzyme tests.
Diagnosis
Diagnosing ALL begins with a medical history and physical examination, complete blood count, and blood smears. Because the symptoms are so general, many other diseases with similar symptoms must be excluded. Typically, the higher the white blood cell count, the worse the prognosis. Blast cells are seen on blood films in 90% of cases. A bone marrow biopsy is conclusive proof of ALL. A spinal tap will tell if the spinal column and brain has been invaded.
Pathological examination, cytogenetics (particularly the presence of Philadelphia chromosome) and immunophenotyping, establish whether the "blast" cells began from the B lymphocytes or T lymphocytes. DNA testing can establish how aggressive the disease is; different mutations have been associated with shorter or longer survival.
Medical imaging (such as ultrasound or CT scanning) can find invasion of other organs commonly the lung, liver, spleen, lymph nodes, brain kidneys and reproductive organs.
Pathophysiology
The cause of most ALL is not known. In general, cancer is caused by damage to DNA that leads to uncontrolled cellular growth and spread throughout the body, either by increasing chemical signals that cause growth, or interrupting chemical signals that control growth. This damage may be caused by environmental factors such as chemicals, drugs or radiation.
In leukemias, including ALL, chromosomal translocations occur regularly. It is thought that most translocations occur before birth during fetal development. These translocations may trigger oncogenes to "turn on", causing unregulated mitosis where cells divide too quickly and abnormally, resulting in leukemia.
Some families have a hereditary predisposition to ALL
ALL is associated with exposure to radiation and chemicals in animals and humans. The association of radiation and leukemia in humans has been clearly established in studies of victims of the Chernobyl nuclear reactor and atom bombs in Hiroshima and Nagasaki. In animals, exposure to benzene and other chemicals can cause leukemia. Epidemiological studies have associated leukemia with workplace exposure to chemicals, but these studies are not as conclusive. Patients who are treated for other cancers with radiation and chemotherapy often develop leukemias as a result of that treatment.
Cytogenetics
Cytogenetics, the study of characteristic large changes in the chromosomes of cancer cells, has been increasingly recognized as an important predictor of outcome in ALL.
Cytogenetic change Risk category
Philadelphia chromosome Poor prognosis
t(4;11)(q21;q23) Poor prognosis
t(8;14)(q24.1;q32) Poor prognosis
Complex karyotype (more than four abnormalities) Poor prognosis
Low hypodiploidy or near triploidy Poor prognosis
High hyperdiploidy Good prognosis
del(9p) Good prognosis
Classification
Subtyping of the various forms of ALL used to be done according to the French-American-British (FAB) classification, which was used for all acute leukemias (including acute myelogenous leukemia, AML). As ALL is not a solid tumour, the TxNxMx notation as used in solid cancers is of little use.
The FAB classification was:
ALL-L1: small uniform cells
ALL-L2: large varied cells
ALL-L3: large varied cells with vacuoles (bubble-like features)
Each subtype is then further classified by determining the surface markers of the abnormal lymphocytes, called immunophenotyping. There are 2 main immunologic types: pre-B cell and pre-T cell. The mature B-cell ALL (L3) is now classified as Burkitt leukemia/lymphoma. Subtyping helps determine the prognosis and most appropriate treatment in treating ALL.
Some cytogenetic subtypes have a worse prognosis than others.
A translocation between chromosomes 9 and 22, known as the Philadelphia chromosome, occurs in about 20% of adult and 5% in pediatric cases of ALL.
A translocation between chromosomes 4 and 11 occurs in about 4% of cases and is most common in infants under 12 months.
Not all translocations of chromosomes carry a poorer prognosis. Some translocations are relatively favorable. For example, Hyperdiploidy (>50 chromosomes) is a good prognostic factor.
Treatment
The earlier acute lymphocytic leukemia is detected, the more effective the treatment. The aim is to induce a lasting remission, defined as the absence of detectable cancer cells in the body (usually less than 5% blast cells on the bone marrow).
Treatment for acute leukemia can include chemotherapy, steroids, radiation therapy, intensive combined treatments (including bone marrow or stem cell transplants), and growth factors.
[edit] Chemotherapy
Chemotherapy is the initial treatment of choice. Most ALL patients end up receiving a combination of different treatments. There are no surgical options, due to the body-wide distribution of the malignant cells.
As the chemotherapy regimens can be intensive and protracted (often about 2 years in case of the GMALL UKALL, HyperCVAD or CALGB protocols; about 3 years for males on COG protocols), many patients have an intravenous catheter inserted into a large vein (termed a central venous catheter or a Hickman line), or a Portacath (a cone-shaped port with a silicone nose that is surgically planted under the skin, usually near the collar bone, and the most effective product available, due to low infection risks and the long-term viability of a portacath). Since ALL cells sometimes penetrate the Central Nervous System (CNS), most protocols include delivery of chemotherapy into the CNS fluid. More advanced centers deliver the drug through Ommaya reservoir (a device surgically placed under the scalp and used to deliver drugs to the CNS fluid and to extract CNS fluid for various tests). More traditional centers would perform multiple lumbar punctures as needed for testing and treatment delivery.
Radiation therapy
Radiation therapy is used on painful bony areas, in high disease burdens, or as part of the preparations for a bone marrow transplant (total body irradiation). Radiation in the form of whole brain radiation is also used for central nervous system prophylaxis, to prevent recurrence of leukemia in the brain. Whole brain prophylaxis radiation used to be a common method in treatment of children's ALL. Recent studies showed that CNS chemotherapy provided results as favorable but with less developmental side effects. As a result, the use of whole brain radiation has been more limited.
Epidemiology
The number of annual ALL cases in the US is roughly 4000, 3000 of which inflict children. ALL accounts for approximately 80 percent of all childhood leukemia cases, making it the most common type of childhood cancer. It has a peak incident rate of 2-5 years old, decreasing in incidence with increasing age before increasing again at around 50 years old. ALL is slightly more common in males than females. There is an increased incidence in people with Down Syndrome, Fanconi anemia, Bloom syndrome, Ataxia telangiectasia, X-linked agammaglobulinemia and Severe combined immunodeficiency.
Prognosis
Advancements in medical technology and research over the past four decades in the treatment of ALL has improved the overall prognosis significantly from a zero to 20-75 percent survival rate, largely due to the continuous development of clinical trials and improvements in bone marrow transplantation (BMT) and stem cell transplantation (SCT) technology.
It is worth noting that medical advances in recent years, both through matching the best treatment to the genetic characteristics of the blast cells and through the availability of new drugs, are not fully reflected in statistics that usually refer to five-year survival rates. The prognosis for
Leukemia — Comprehensive overview covers symptoms, causes, risk factors, treatment of this blood-related cancer.
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