Which type of leukemia is most commonly found in the United States?

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia found in the United States, particularly among adults. CLL typically affects older adults and is characterized by the accumulation of functionally incompetent lymphocytes, mostly B-cells, in the blood, bone marrow, and lymphoid tissues. The gradual progression of this leukemia often allows patients to be asymptomatic for years, making it more frequently diagnosed in routine blood tests or check-ups.

In comparison to the other types of leukemia, while acute lymphocytic leukemia and acute myelogenous leukemia can present suddenly and are more common in children, they do not match the incidence rate of CLL in adults. Chronic myelogenous leukemia is relatively less common than CLL and is associated with a specific genetic mutation known as the Philadelphia chromosome, affecting a smaller proportion of the population. Thus, CLL stands out as the predominant type of leukemia diagnosed in the U.S. population, especially among older age groups.