High Lifetime Incidence of Adult Acute Lymphoblastic Leukemia among Hispanics in California

Background: The higher incidence of acute lymphoblastic leukemia (ALL) among Hispanic children relative to that in other racial/ethnic groups is wellknown. We evaluated the incidence patterns of ALL in adults. Methods: We analyzed the incidence patterns of ALL (International Classification of Diseases for Oncology 3 codes 9835-9837) among all patients diagnosed from 1988 to 2004 in California using data from the California Cancer Registry to determine whether adult Hispanics also had higher incidence rates of ALL compared with non-Hispanic Whites (Whites). Age-adjusted incidence rates (AAIR), incidence rate ratios (IRR), and 5-year survival rates were obtained using SEER*Stat. AAIRs of other leukemia subtypes and IRRs relative to non-Hispanic Whites were also examined as references for ALL. Results: AAIRs of ALL in Hispanic males and females ages 20 to 54 years were higher compared with those in White males and females (IRR, 1.99; 95% confidence interval, 1.74-2.28 and IRR, 1.91; 95% confidence interval, 1.60-2.25, respectively). A higher AAIR of ALL was also observed among older (55+ years) Hispanic females (IRR, 1.84; 95% confidence interval, 1.52-2.21.), but not in males (IRR, 1.07; 95% confidence interval, 0.84-1.34). Among Hispanics, low socioeconomic status was associated with a higher AAIR compared with high/middle socioeconomic status (IRR, 1.33; 95% confidence interval, 1.04-1.70). The respective 5-year survival rates among ALL patients were 38% and 30% for Whites and Hispanics ages 20 to 54 years, and 8% and 12% for patients 55 years of age or older. Compared with other racial/ethnic groups, Hispanics did not have an increased IRR of the other major leukemia subtypes. Conclusion: Hispanics experience a higher incidence of ALL throughout life, but not other subtypes. (Cancer Epidemiol Biomarkers Prev 2009;18(2):611-5)