Comparative epidemiology of cancers of the colon, rectum, prostate and breast in Shanghai, China versus the United States.

Incidence rates of cancers of the colon, rectum, female breast, and prostate were compared among native Chinese (Shanghai), Chinese-American, and American populations. Americans had fourfold higher age-adjusted rates of colon cancer, and twofold higher rates of rectal cancer than Chinese, which is consistent with elevated per capita intake of fat and lower intake of cereals and vegetables in the US. Incidence rates of colon and rectal cancers in Chinese-Americans were nearly equal to the American rates, suggesting that the risk for tumour development in the lower intestinal tract is rapidly increased with transition to the US diet. Rates of prostate cancer and postmenopausal breast cancer were 26-fold and tenfold higher in Americans than in Chinese, whereas the rates for Chinese-Americans were intermediate. Environmental factors such as dietary fat apparently had a more gradual effect in promoting cancers of the breast and prostate relative to their influence on neoplasms of the lower intestinal tract.