Dr. Tabo Sikaneta, MD
Clinical and Research Fellow
Massachusetts General Hospital
Harvard Medical School
Chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL) are malignant hematologic disorders that predominantly affect the middle-aged and elderly. Although they share certain features in their clinical presentations, these two neoplasms differ significantly with regard to epidemiology, pathogenesis, prognosis, and management issues. This article will compare and contrast CML with CLL in order to highlight these important clinical differences. Particular attention will be given to the treatment issues faced by elderly patients with these chronic leukemias, and to the role that primary care physicians may play in the management of these diseases.
Definition and Epidemiology
CML is the clonal proliferation of hematopoietic stem cells. CLL is the clonal proliferation of small, long-lived, mature B lymphocytes. CML is less common, with an annual incidence of 1-2 per 100,000 members of the general US population. It has an equal distribution among both sexes.1 Both CML and CLL affect whites more than blacks, are not familial, and are not related to a history of known carcinogenic agent exposure.2 Although the median age of onset of CML is 53, a sizeable minority (10-30%) contract CML after age 60.
