Trends in leukemia incidence and survival in the United States (1973-1998).

BACKGROUND: It is estimated that each year, approximately 30,800 individuals will be diagnosed with leukemia in the United States and 21,700 individuals will die of the disease. Although the overall incidence of leukemia has been declining in the United States, recent reports suggest that incidence rates may be increasing for certain age and racial groups.

METHODS: Leukemia incidence (including acute lymphoblastic leukemia [ALL], acute myeloid leukemia [AML], chronic myeloid leukemia [CML], and chronic lymphoblastic leukemia [CLL]) and 5-year survival rates were obtained from the Surveillance, Epidemiology, and End Results (SEER) program. Specific rates for age (birth-19, 20-44, 45-64, and 65 + years), gender, and race (black, white) were also examined.

RESULTS: A total of 66,404 cases of leukemia were identified for the period 1973-1998 in the nine reporting SEER sites. For children younger than 20 years old, the overall incidence rate of leukemia increased significantly (estimated annual percent change [EAPC] = 0.5%, 95% confidence interval [CI] = 0.1-0.9), whereas the rate decreased significantly among the group 65 years and older (EAPC = - 0.3, 95% CI = - 0.5 to - 0.1). Incidence rates for CLL and CML decreased significantly during this time period, whereas incidence rates for AML remained stable. Children younger than 20 years old experienced a 15% increase in the 5-year survival rates for both ALL and AML when comparing the two 10-year periods of 1974-1983 and 1984-1993. In contrast, there was little overall improvement in survival for adults 45 years and older. In particular, there was a notable decrease in the overall 5-year survival for blacks older than 65 years and for black males older than 44 years.

CONCLUSIONS: Although the current study confirmed some of the results noted in other populations, the observed overall decline in leukemia survival for blacks is surprising and warrants further investigation.