Objectives: To estimate misclassification of ethnicity and cancer incidence in Southeast Asian children using the population-based California Cancer Registry.
Methods: Asian race/ethnicity was evaluated using lists of Asian surnames. Average annual incidence rates (per million) for 1988 to 1992 were calculated for non-Hispanic white, black, Hispanic, and Asian children (age <15 years). Proportional incidence ratios (PIRs) for 1988 to 1995 were used to compare Southeast Asian children to non-Hispanic white children.
Results: Of the Asian children, 4.2% (30/722) were misclassified by subgroup, predominantly Hmong listed as Laotian. The Asian cancer rate was 134.2 versus 159.2 for non-Hispanic whites. The germ cell tumor rate was higher in Asians (9.9) than in non-Hispanic whites (4.8), but the Wilms tumor rate was two-thirds lower (3.1 vs. 9.2). The rates of Hodgkin lymphoma and central nervous system tumors were lower (2.8 vs. 5.6 and 20.0 vs. 33.8) in Asians than non-Hispanic whites. Compared with non-Hispanic whites, the PIR for Wilms tumor in Southeast Asian children was reduced (PIR = 0.1). Southeast Asian children had increased PIRs for Burkitt lymphoma (PIR = 2.6) and leukemias not classified as acute lymphocytic leukemia or acute nonlymphocytic leukemia (PIR = 3.5).
Conclusions: Accurate race/ethnicity classification of Southeast Asian children is a concern. Marked differences were found in the incidence and PIRs of specific cancers among Southeast Asian children, other Asian children, and other children in California.