Terence Herman, M.D.
DHR Health Oncology Institute
Leukemia is a cancer of the bone marrow cells that produce the three major components of blood cells: the white cells, the red cells, and the platelets. The most common type in children is acute lymphoblastic leukemia (ALL) and in adults is acute myeloblastic leukemia (AML), both of these in the cells that acutely fight infection, the granulocytes. Since the leukemia cells usually overgrow the marrow space and crowd out the normal cells, anemia (too few red cells), thrombocytopenia (too few platelets), and leukocytosis (too many immature white cells) result.
The symptoms of leukemia are varied, but fatigue from the anemia, bleeding from the mucous membranes or into the skin from low platelets, and infections from inadequate mature granulocytes commonly occur.
The diagnosis is usually made or suspected on the complete blood count test and confirmed with a biopsy of the bone marrow. There are several subtypes of leukemia, and tests to separate them are done by pathologists skilled in the diagnosis of hematological cancers. Those tests include how the cells look (morphology) and what chromosomal and mutational patterns are seen.
In terms of cause, there are two main categories: 1. secondary, after a known bone marrow toxin, such as prior chemotherapy or radiation exposure or after prolonged bone marrow dysfunction (myelodysplastic syndrome); and 2. idiopathic, cause unknown. In general, secondary leukemias have a worse prognosis.
Modern treatment for leukemia began in the 1960s and has improved greatly over the years. Children with ALL are routinely cured, even if they are prognostically high risk (age under one or over 10, and/or white blood count over 50,000 are the most important factors).
For both adults and children, combinations of chemicals directly toxic to growing cells are used repetitively after allowing for normal bone marrow cells to recover. For high-risk patients, very high dose chemotherapy is used, with replacement of bone marrow cells with a genetically similar donor. Donor cells also provide an immunological attack against the leukemic cells. In addition, just in the last few years, removal of the patient’s lymphocytes and programming those cells to kill the leukemia cells prior to injecting them back into the patient has proven very beneficial, especially in ALL.
Overall, for low- or standard-risk pediatric ALL, over 90% will be cured, while for adults only about 40% will be cured. In the case of AML, about 65% of children are cured, but only about 40% of adults are, although cell type and chromosomal and molecular findings affect these numbers.
There is one special type of AML Hispanic patients should be aware of. Acute promyelocytic leukemia (APL) is more common in Hispanics and in younger patients. Fully one-third of AML in South America is APL, which often presents with bleeding, but it is over 90% curable, regardless of age.
Acute leukemias are not common illnesses. There are about 20,000 AML and
6,600 ALL patients in the U.S. per year. However, earlier diagnosis is beneficial, and the complete blood count (CBC) is an easy and effective screening test. People with unexplained fatigue, bleeding, or infection should be screened with a CBC.
For more information or to schedule an appointment with one of our experts, contact DHR Health Oncology Institute at 956-362-2250.
