Acute lymphoblastic leukemia (ALL) is the most prevalent cancer among children and adolescents in the United States, representing 20% of all cancers diagnosed in persons aged <20 years, or >3,000 new cases each year (1). Past studies reported increasing trends of ALL overall and among Hispanics, but these represented ≤28% of the U.S. population and did not provide state-based estimates (1–3). To describe U.S. ALL incidence rates and trends among persons aged <20 years during 2001–2014, CDC analyzed rigorous data (based on established publication criteria) from the United States Cancer Statistics data set, which includes incidence data on approximately 15,000 new cases per year of all types of invasive cancer among children and adolescents aged <20 years (4). The data set represented 98% of the U.S. population during the study period. Overall incidence of pediatric ALL during 2001–2014 was 34.0 cases per 1 million persons and among all racial/ethnic groups was highest among Hispanics (42.9 per 1 million). Both overall and among Hispanics, pediatric ALL incidence increased during 2001–2008 and remained stable during 2008–2014. ALL incidence was higher in the West than in any other U.S. Census region. State-specific data indicated that the highest rates of pediatric ALL incidence were in California, New Mexico, and Vermont. These demographic and geographic ALL incidence data might better inform public health interventions targeting the following areas: exposures to recognized risk factors for leukemia; ALL treatment, including clinical trial enrollment; survivorship care planning; and studies designed to understand the factors affecting changes in pediatric cancer incidence.

The United States Cancer Statistics data set includes cancer incidence data from CDC’s National Program of Cancer Registries and the National Cancer Institute’s Surveillance, Epidemiology, and End Results program (4). Data on new cases of cancer diagnosed during 2001–2014 were obtained from population-based cancer registries affiliated with the National Program of Cancer Registries or Surveillance, Epidemiology, and End Results programs. Incidence data for all registries except the District of Colombia, Mississippi, and Nevada met United States Cancer Statistics publication criteria during 2001–2014, and represented 98% of the U.S population.* This report includes cases diagnosed among children and adolescents aged <20 years and includes International Classification of Diseases for Oncology, Third Edition^† codes 9728–9729, 9811–9818, and 9835–9837 as grouped by the International Classification of Childhood Cancer.^§ Cases were included if ALL was the first or only cancer diagnosed and was confirmed microscopically or by positive laboratory test or marker study. Recurrent cases of ALL were not included in this report.

Age-adjusted rates were calculated using statistical software. All rates were expressed per 1 million persons and were age-adjusted to the 2000 U.S. standard population.^¶ Age-adjusted incidence trends were quantified using annual percent change (APC) calculated using joinpoint regression. Statistically significant APCs were different from zero (p<0.05). A maximum of two joinpoints were used to determine a change of direction in trends during the study period. Rates and trends were estimated by sex, age group, race/ethnicity, state, U.S. Census region,** county-level economic status, and rural/urban status.

During 2001–2014, a total of 38,136 new pediatric ALL cases were diagnosed in the United States (Table). Overall incidence of ALL was 34.0 cases per 1 million. Rates were highest in children aged 1–4 years (75.2 per 1 million) and were higher in males (38.0) than in females (29.7). Among all racial/ethnic groups, the highest incidence rate (42.9 per 1 million) was among Hispanics, followed by non-Hispanic whites (34.2 per 1 million). The lowest incidence (18.7) occurred among non-Hispanic blacks. Pediatric ALL incidence rates in the 25% of U.S. counties with the highest economic status were higher than rates in the 25% of counties with the lowest economic status and were higher in metropolitan areas with ≥1 million persons than in nonmetropolitan areas. Rates were highest in the West (38.5) followed by the Northeast (34.8), Midwest (32.4), and South (31.6) Census regions, and, among states, were highest in Vermont (41.9), California (40.8), and New Mexico (39.1) (Figure 1) (Supplementary Table 1, https://stacks.cdc.gov/view/cdc/47662). State-specific ALL incidence by race/ethnicity ranged from 10.1–27.9 per 1 million among non-Hispanic blacks to 25.1–45.0 among non-Hispanic whites and 27.3–48.5 among Hispanics (Supplementary Table 2, https://stacks.cdc.gov/view/cdc/47663).

Overall pediatric ALL incidence increased 1.9% per year during 2001–2008, and then remained stable during 2008–2014 (Figure 2). Incidence increased among males during 2001–2008 and among children aged 5–9 years and 10–14 years during 2001–2010 and 2001–2014, respectively, as well as in metropolitan areas with populations ≥1 million during 2001–2008 (Table). Among Hispanics, rates increased during 2001–2008 (APC 2.5, 95% confidence interval = 0.3–4.7) and were stable (nonsignificant decrease) during 2008–2014; pediatric ALL incidence rates were stable in all other racial/ethnic groups. State-specific analysis indicated that pediatric ALL incidence increased during all or part of 2001–2014 in four states: Alabama, Maryland, Massachusetts, and New York (Supplementary Table 1, https://stacks.cdc.gov/view/cdc/47662).