Epidemiologic studies of cancer in minority groups in the western United States.
Of 13 cancers that tend to occur at lower rates in aboriginal Americans or in the native lands of Japanese, Chinese, and Spanish-speaking persons than in United States whites, rates for all but one (laryngeal) have increased in migrants to the United States. In addition to leukemia, these 13 cancers include neoplasms that have been related, at least in part, to a diet high in animal fats or proteins (colon and rectum cancer); reproductive and endocrinologic factors and a diet high in animal fats or protein (prostate, ovary, corpus uteri, breast, and testis cancer); chemical carcinogens (lung, larynx, bladder, and pancreas cancer); and a common infectious agent that, like polio viruses, causes clinically overt disease with a frequency directly related to age of patient at initial infection (Hodgkin's disease). Of 9 cancers that occur at higher rates in aboriginal Americans or in one or more of the native lands of migrants than in United States whites, the rates of 5 tend to decrease in migrants. These include cancers that may be related to food preservation (stomach cancer); products of microorganisms that may contaminate foods (esophagus and liver cancer); and infectious agents (nasopharynx, cervix uteri, and liver cancer). In addition, rates of cancer of the thyroid are high in aboriginal Americans; those of the gallbladder are high in individuals of native American ancestry and in Japanese; incidence of salivary gland tumors is high in Alaskan natives and Colombians; and rates of kidney cancer are high in Alaskan natives. Five types of epidemiologic studies are described that should be conducted in the migrants and in their countries of origin and adoption to elucidate further the etiology of various neoplasms.