Improving Cancer Incidence Estimates for American Indians and Alaska Natives in the Pacific Northwest

In many disease registries, including cancer registries, misclassification of American Indian and Alaska Native (AI/AN) race is common. This type of misclassification threatens the validity of existing estimates of disease occurrence in this population.1–9 From a public health perspective, the underestimation of cancer incidence has a potentially great effect, as appropriate cancer control measures are less likely to be implemented in light of spuriously low rates. The problem of racial misclassification of AI/AN race in cancer registries appears to be widespread: investigators in several states have shown that AI/AN race is frequently underreported in both federally sponsored and state-supported cancer registries.4–8 We conducted record linkage studies to evaluate the extent of racial misclassification of AI/ANs in the cancer registries for Idaho, Oregon, and Washington states that constitute the administrative unit of the Indian Health Service (IHS) known as the Portland Area IHS. We also calculated estimates of cancer incidence among AI/ANs in these states.