A bone marrow biopsy is almost always performed to confirm the diagnosis and to distinguish AML from other types of leukemia.
Acute myeloid leukemia (AML), is a cancer of the myeloid line of white blood cells. It is transparent by the rapid proliferation of abnormal cells which accumulate in the bone marrow and interfere with the production of normal blood cells. Acute myelocytic leukemia, also known as acute myelogenous leukemia, may lead to overgrowth of the gums and blurred vision. Acute leukemia is believed to begin in a single somatic hematopoietic progenitor that transforms to a cell incapable of normal differentiation. Many of these cells no longer possess the normal property of apoptosis, or programmed cell death. Leukemogenesis is frequently associated with chromosomal abnormalities and gene translocations. Many translocations are characteristic of a particular subtype of acute leukemia and often convey additional prognostic information to the clinician.
Tobacco smoking appears to increase the incidence of this form of leukemia. The signs and symptoms of acute myelocytic leukemia result from the fact that, as the leukemic clone of cells grows, it tends to displace or interfere with the development of normal blood cells in the bone marrow. This leads to neutropenia, anemia, and thrombocytopenia. Acute myeloid leukemia is the most common acute leukemia affecting adults, and its incidence increases with age. Although several risk factors for acute myelocytic leukemia have been identified, the specific cause of AML remains unclear. As an acute leukemia, AML progresses rapidly and is typically fatal within weeks or months if left untreated. Exposure to certain chemicals can also cause leukemia. Workers exposed to benzene over long periods have an increased risk of developing acute myelocytic leukemia.
Tests such as chest X rays and examination of the spinal fluid for leukemic cells can help doctors determine how far the disease has spread. The identification of acute myelocytic leukemia is also similar to that of acute lymphocytic leukemia. The symptoms of AML are caused by replacement of normal bone marrow with leukemic cells, resulting in a drop in red blood cells, platelets, and normal white blood cells. These symptoms include fatigue, shortness of breath, easy bruising and bleeding, and increased risk of infection. In rare cases, a mediastinal mass may cause symptoms of respiratory insufficiency or superior vena cava syndrome.
Acute myeloid leukemia is a potentially improvable disease, but only a minority of patients are cured with current therapy. AML is treated initially with chemotherapy aimed at inducing a remission; some patients may go on to receive a hematopoietic stem cell transplant. Once acute myelocytic leukemia is in remission, the person usually receives a few courses of additional chemotherapy a few weeks or months after the initial treatment to help ensure that as many leukemia cells as possible are destroyed. People who have not responded to treatment and younger people who are in remission but who are likely to have a high rate of relapse may be given high-dose chemotherapy with stem cell transplantation. A new drug, gemtuzumab ozogamicin, which combines an antibody with a chemotherapy drug as an attempt to specifically "target" the leukemia cells, is effective in some people after relapse has occurred. The long-term benefits of the drug have not been determined.
By Juliet Cohen
