Many of the remaining children will be diagnosed with acute myeloid leukemia (AML). Chronic leukemias are very rare in children. ALL is most common in early childhood, peaking between ages 2 and 3 years of age. AML is most common during the first 2 years of life and is less common among older children. AML cases start to increase again during the teenage years, with AML becoming the most common acute leukemia in adults over 55 years of age. ALL is slightly more common among white children than among African-American and Asian-American children, and is more common in boys than in girls. AML is equally rare among boys and girls of all races.

The 5-year survival rate for ALL has greatly increased over time, and is now nearly 80%, primarily due to advances in treatment. Five-year survival rates of children with AML have also increased over time to about 40%. Of course, the outlook for each patient is different, depending mostly on prognostic factors discussed in "How is Childhood Leukemia Staged?" The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Many of these patients live much longer than 5 years after diagnosis, and 5-year rates are used to produce a standard way of discussing prognosis. Of course, 5-year survival rates are based on patients diagnosed and initially treated more than 5 years ago. Advances in treatment often result in a more favorable outlook for recently diagnosed patients.