—leukemic, adj./looh kee"mee euh/, n. Pathol.any of several cancers of the bone marrow that prevent the normal manufacture of red and white blood cells and platelets, resulting in anemia, increased susceptibility to infection, and impaired blood clotting.Also, leucemia.[1850-55; earlier leuchaemia < G Leukämie (1848). See LEUCO-, -EMIA]
* * *Cancer of blood-forming tissues with high levels of leukocytes.Radiation exposure and hereditary susceptibility are factors in some cases. In acute leukemias, anemia, fever, bleeding, and lymph-node swelling develop rapidly. Acute lymphocytic leukemia, found mostly in children, was once over 90% fatal in six months. Drug therapy can now cure more than half these children. Acute myelogenous (granulocytic) leukemia, found mostly in adults, has frequent remissions and recurrences, and few patients survive long. Chronic myelogenous leukemia most often begins in the 40s; weight loss, low fever, weakness, and other symptoms may not develop immediately. Chemotherapy helps the symptoms but may not prolong life. Chronic lymphocytic leukemia, mostly in the elderly, may be inactive for years. Survival rates are better than in myelogenous leukemia; most deaths are caused by infection or hemorrhage.
* * *a cancer of the blood-forming tissues characterized by a large increase in the numbers of white blood cells (leukocytes (leukocyte)) in the circulation or bone marrow. A number of different leukemias are classified according to the course of the disease and the predominant type of white blood cell involved. Some types of leukemia have been related to radiation exposure, as noted in the Japanese population exposed to the first atomic bomb at Hiroshima; other evidence suggests hereditary susceptibility.Leukemias are defined as either acute or chronic and as either myelogenous (from bone marrow) or lymphocytic (involving lymphocytes (lymphocyte)). These characteristics are used to designate almost all cases as one of four types—acute myelogenous, acute lymphocytic, chronic myelogenous, and chronic lymphocytic leukemia. Acute leukemias affect immature cells; the disease develops rapidly, with symptoms including anemia, fever, bleeding, and swelling of the lymph nodes. Immature leukemia cells continue to divide in the bone marrow, which leads to rapid death if left untreated. In chronic leukemia the cells develop and are transported to the tissues, but the cells do not function normally. Myelogenous leukemia affects granulocytes (blood) and monocytes (blood), white blood cells that destroy bacteria and some parasites. The most common form in children, acute lymphocytic leukemia, once killed more than 90 percent of its victims within six months. With new drug therapies (therapeutics), the majority of acute lymphocytic patients now achieve complete remission, with no evidence of malignant cells in the blood. With continued therapy, more than half remain free of disease for five years or longer. These patients are presumed to be cured.Results of treatment for other leukemias have not been as positive. In acute myelogenous leukemia, which is more common in adults, patients can experience complete remission, but recurrence is common.Chronic leukemias also occur more frequently in adults. These are characterized by a more gradual onset and a more protracted course. Chronic myelogenous leukemia, which has a peak incidence among adults in their 40s, may remain quiescent for long periods before symptoms such as weight loss, low fever, and weakness develop.Chronic lymphocytic leukemia occurs primarily in elderly people and may be inactive for months or years. The leukemia itself is rarely the cause of death, but it renders the patient vulnerable to infection or hemorrhage.
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