Leukemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases. In turn, it is part of the even broader group of diseases affecting the blood, bone marrow, and lymphoid system, which are all known as hematological neoplasms.
In 2000, approximately 256,000 children and adults around the world developed some form of leukemia, and 209,000 died from it. About 90% of all leukemias are diagnosed in adults. Classification Clinically and pathologically, leukemia is subdivided into a variety of large groups. The first division is between its acute and chronic forms:
Four major kinds of leukemia Cell type Acute ChronicLymphocytic leukemia Acute lymphoblastic Chronic lymphocytic (or "lymphoblastic") leukemia (ALL) leukemia (CLL)Myelogenous leukemia Acute myelogenous Chronic myelogenous (also "myeloid" or leukemia (AML) leukemia (CML) "nonlymphocytic") (or myeloblastic)
Acute Lymphoblastic Leukemia Acute lymphoblastic leukemia (ALL) is a form of leukemia, or cancer of the white blood cells characterized by excess lymphoblasts. 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 (infiltrating) to other organs. ALL is most common in childhood with a peak incidence at 2–5 years of age, and another peak in old age. The overall cure rate in children is about 80%, and about 45%-60% of adults have long-term disease-free survival
Acute refers to the relatively short time course of the disease (being fatal in as little as a few weeks if left untreated) to differentiate it from the very different disease of chronic lymphocytic leukemia, which has a potential time course of many years. It is interchangeably referred to as Lymphocytic or Lymphoblastic. This refers to the cells that are involved, which if they were normal would be referred to as lymphocytes but are seen in this disease in a relatively immature (also termed blast) state.
Cases of Acute Lymphocytic Leukemia are detected by:Swelling in the abdomenEnlarged lymph nodesBone or joint painSymptoms from an enlarged thymus
Tests Used to Look for ALL Blood tests Bone marrow aspiration and biopsy Lumbar puncture (spinal tap) Lymph node biopsy
Lab Tests Used to Diagnose and Classify ALL Blood cell counts and blood cell exam (peripheral blood smear) Blood chemistry and coagulation tests Routine exams under a microscope Cytochemistry Flow cytometry and immunohistochemistry Cytogenetics Fluorescent in situ hybridization (FISH) Polymerase chain reaction (PCR)
Risk Factors for ALL Radiation exposure Certain chemical exposures Chemotherapy drugs Benzene Certain viral infections Infection with human T-cell lymphoma/leukemia virus-1 (HTLV-1) Epstein-Barr virus (EBV)
Inherited syndromes Down syndrome Klinefelter syndrome Fanconi anemia Bloom syndrome Ataxia-telangiectasia Neurofibromatosis Race/ethnicity ALL is more common in whites than in African Americans
Gender ALL is slightly more common in males than in females. Having an identical twin with ALL Uncertain, unproven or controversial risk factors Exposure to electromagnetic fields (such as living near power lines or using cell phones) Workplace exposure to diesel, gasoline, pesticides, and certain other chemicals Smoking Exposure to hair dyes
Statistics/Prevalence Statistics on acute lymphocytic leukemia based on rates from 2000 to 2002 indicate that 1 out of every 870 people born today will be diagnosed with ALL at some point during their life. Other statistics show that the median age at diagnosis was 11 years of age and the median age at death was 47 years of age. The American Cancer Society estimated that 3,970 people (2,180 men and 1,790 women) would be diagnosed with acute lymphocytic leukemia (acute lymphoblastic leukemia, or ALL) in 2005.
From 1998 to 2002, the median age at diagnosis for acutelymphocytic leukemia was 11 years. The percentages ofpeople diagnosed with ALL based on age are: 63.6 percent were diagnosed under age 20 9.7 percent between 20 and 34 5.8 percent between 35 and 44 6.1 percent between 45 and 54 5.3 percent between 55 and 64 4.5 percent between 65 and 74 3.4 percent between 75 and 84 1.5 percent 85+ years of age.
The age-adjusted acute lymphocytic leukemia incidence ratewas 1.5 per 100,000 men and women per year.From 1998 to 2002, the median age at death from acutelymphocytic leukemia was 47 years of age. The percentages ofpeople who died from ALL based on age are: 22.2 percent died under age 20 15.7 percent between 20 and 34 9.6 percent between 35 and 44 10.7 percent between 45 and 54 11.1 percent between 55 and 64 12.9 percent between 65 and 74 12.4 percent between 75 and 84 5.6 percent 85+ years of age.
The age-adjusted acute lymphocytic leukemia death rate was 0.5 per 100,000 men and women per year in the United States. The five-year relative survival rates by race and sex are: 65.2 percent for Caucasian men 66.7 percent for Caucasian women 54.2 percent for African American men 54.8 percent for African American women.