Over 11,600 new cases of chronic leukemia are diagnosed in the United States every year. The disease is most often associated with advanced age: most people diagnosed are between forty and seventy years of age. Although the risk of chronic leukemia rises with age, any age group may be affected. Children comprise two percent of all reported cases.
Progression of the Disease
The disease occurs when abnormal white blood cells (WBCs) build up in the bloodstream. Unlike acute forms of the cancer, chronic varieties progress slowly. While the abnormal blood cells do not reproduce rapidly, they are longer-lived than ordinary blood cells. By outlasting healthy cells, the cancerous WBCs eventually accumulate in large numbers.
Chronic leukemia symptoms develop slowly, and are vague; they often resemble a number of other, less serious medical conditions. Fatigue and fever are common. Unexplained weight loss may occur, and individuals may develop night sweats. Other symptoms can include heightened rates of infection, easy bruising, and severe bleeding.Abnormal WBCs tend to accumulate in the spleen. This can cause a condition known as splenomegaly, or enlarged spleen. The condition causes a feeling of abdominal discomfort. People with enlarged spleens may feel full after eating even small amounts of food.
The disease can cause a number of blood-related disorders. Anemia, or a lack of red blood cells, is a common cause of fatigue.
Neutropenia is a lack of neutrophils, a type of WBC that is responsible for combating bacteria, hence those with neutropenia have infections with increased frequency and severity.
Hypogammaglobulinema also affects the immune system. The condition indicates a low level of gamma globulin antibodies, proteins necessary to fight infection.
Thrombocytopenia indicates low levels of platelets. Platelets are responsible for blood clotting. Insufficient amounts of platelets lead to easy bruising and bleeding.
Finally, a small percentage of people develop leucostatis due to abnormally high WBC levels. Leucostatis can cause headaches, confusion, dizziness and can affect the lungs and heart.
Because symptoms develop so slowly, many cases of chronic leukemia are diagnosed only when routine blood tests reveal unusual results. From there, more specific blood tests and bone marrow biopsies are used to finalize a diagnosis.
CML and CLL
The two distinct types of chronic leukemia are CML and CLL. CML (chronic myelogenous leukemia) reflects abnormal changes in myeloid precursor cells, immature cells that eventually develop into granulocytes, monocytes, and platelets; cells that combat infection and assist in blood clotting. CLL (chronic lymphoblastic leukemia) begins in the bone marrow lymphoid tissue, where WBCs are formed, and the malignant cells resemble normal lymphocytes