Leukemia: an overview for primary care.

Leukemia is a clonal proliferation of hematopoietic stem cells in the bone marrow. The four broad subtypes most likely to be encountered by primary care physicians are acute lymphoblastic, acute myelogenous, chronic lymphocytic, and chronic myelogenous. Acute lymphoblastic leukemia occurs more often in children, whereas the other subtypes are more common in adults. Risk factors include a genetic predisposition as well as environmental factors, such as exposure to ionizing radiation. Symptoms are nonspecific and include fever, fatigue, weight loss, bone pain, bruising, or bleeding. A complete blood count usually reveals leukocytosis and other abnormally elevated or depressed cell lines. Patients with suspected leukemia should be referred promptly to a hematologist-oncologist. The diagnosis is confirmed by further examination of the bone marrow or peripheral blood. Treatment may include chemotherapy, radiation, monoclonal antibodies, or hematopoietic stem cell transplantation. Complications of treatment include tumor lysis syndrome and serious infections from immunosuppression. Leukemia survivors should be monitored closely for secondary malignancies, cardiac complications, and endocrine disturbances such as metabolic syndrome, hypothyroidism, and hypogonadism. Five-year survival rates are highest in younger patients and in patients with chronic myelogenous leukemia or chronic lymphocytic leukemia.