Acute leukemia in adult Hispanic Americans: a large-population study

Acute leukemia (AL) is a diverse group of clonal hematopoietic disorders that are broadly categorized into two types: acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL).1, 2, 3 AML is further grouped into acute promyelocytic leukemia (APL, a highly curable disease with a unique and pathognomonic genetic lesion) and non-APL AML. ALL is also further lineage classified into B-cell ALL or T-cell ALL. Unlike older classification systems that defined AL according to how leukemia cells looked and stained under the light microscope,1 the current iteration of the World Health Organization (WHO) classification of hematopoietic neoplasms incorporates cytogenetic and molecular data to provide prognostic and therapeutic information of value to the treating clinician.2, 3 When applied to large-population databases, the WHO framework also provides useful insights into the distribution of AL among ethnic groups, informing on the causative factors of AL, which are at this time poorly understood. For example, in the United States, whites have higher rates of AML compared with other groups.4 B-ALL is uncommon in blacks and Asians, whereas Hispanics have the highest incidence rates (IR) of this leukemia.5 AML appears less common in Hispanics when compared with whites, however, APL appears comparatively more common in Hispanics.6 The varied distribution of AL among these ethnic groups suggests that host susceptibility factors are critical determinants of disease in one group, but not in another. The extent to which the environment interacts with these factors is unknown. In Florida, Hispanics comprise 23.6% of the population, with up to 65% of this group residing in South Florida. About 51% of Hispanics in Florida are native born, 49% are foreign born. In 2015, it is estimated that 3930 new cases of AL will be diagnosed.7 Given the known interaction between ethnicity and AL incidence, we sought for the first time, to better understand the epidemiological patterns of AL distribution throughout Florida. Utilizing the Florida Cancer Data System (FCDS), we analyzed the patterns of B-cell ALL, T-cell ALL, non-APL AML and APL AML among Hispanics and non Hispanic Whites.