The task of disentangling variations in cancer incidence which might be related to race from those attributable to geography is always going to present problems if each race stays in its country of origin. The best opportunity comes from the United States with its great mix of different immigrant races. The figures for the United States have been examined in detail by American epidemiologists and some startling variations have been found. These may of course still not be attributable purely to the racial differences but could reflect the cultural, dietary and economic differences between the different groups within the country. Having acknowledged that we must be cautious in interpreting the causes of the variations, we find that, in general, American blacks have a much higher cancer incidence (5,000 per 1,000,000 per year) than American Indians who represent the other extreme (2,000 per 1,000,000 per year). The overall descending order of cancer incidence among American races goes blacks, whites, Hawaiian, Japanese, Chinese, Hispanics, Filipinos and American Indians. However, this pattern is not uniform across all cancer sites, and for cancer of the stomach, for instance, the Japanese, Hawaiians and American Indians represent the highest-risk group while the whites are at lower risk. For melanoma of the skin, the white-skinned races are, as expected, most vulnerable, whereas blacks have a very low incidence indeed, as do most of the other races with more pigmented skins.
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