Cancer of the urinary bladder in the Pacific Basin.

The incidence of urinary bladder cancer differs markedly among the different ethnic and national groups in the Pacific Basin. Because of these differences, the following colaborative studies can be done to identify and characterize factors associated with bladder cancer: 1) study population groups with different levels of bladder cancer risk who reside in the same geographic setting; 2) study ethnically similar groups who differ in risk and reside in different locations; and 3) study population groups who differ in risks and reside in different geographical regions. Factors possibly related to bladder cancer that have been identified and studied by others include occupational exposure to certain chemicals, cigarette smoking, coffee drinking, artificial sweeteners, certain viruses, radiation exposure, phenacetin, bracken fern, Schistosoma haematobium, tryptophan metabolites, nitrosamines, estrogens, hair dyes, vitamin A, and ascorbic acid. In collaborative studies, the pathologic interpretation of histologic material and the content of the questionnaire should be well standardized, and the laboratory tests should be done at one laboratory. Among the population groups in the Pacific Basin, the Japanese in Hawaii and in Japan provide a unique resource for further investigation with respect to bladder cancer.