ABSTRACT
Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults in
the Western world, accounting for nearly 25% of all leukemias with an estimated annual
age-adjusted incidence of 3 per 100,000 persons in the United States (1,2). The median
age at diagnosis is approximately 70 years, with 81% of the patients diagnosed at age
60 years (1). Under the World Health Organization (WHO) classification, CLL is a B-cell neoplasm, and the entity T-cell CLL has been reclassified as T-cell prolymphocytic
leukemia (PLL) (3). Recent data from the Surveillance, Epidemiology, and End Results
cancer statistics indicate that five-year survival of patients with CLL is 73% (4).
