Cancer mapping as an epidemiologic research resource in China

Cancer mapping is a rich resource for epidemiologic research. The Atlas of Cancer Mortality in the People's Republic of China has become a basis for the correct organization of anti-cancer campaigns, for the investigation of cancer etiology, and for the evaluation of the quality and impact of cancer prevention and control. A series of etiologic clues have been generated and tested from the geographic patterns of cancer mortality at the county level in China, and several prevention studies have been pursued to confirm the hypotheses and to discover reasonable preventive and control measures. This review describes the recent development of cancer epidemiologic research in China through a stepwise approach from cancer mapping to correlation studies to analytical studies (case control and cohort studies) as well as field intervention trials. A clear picture of the incidence and distribution of cancer in the population is useful in the organization of prevention programs, the investigation of cancer etiology, and the evaluation of cancer control activities. Developed countries have systematically collected cancer statistics through vital statistics, establishment of cancer registries, and the conduct of ad hoc surveys of cancer incidence for several decades. China, however, a country with a vast area and a large population, has a relatively short history of cancer control research, and of the accumulation of statistics on cancer mortality and morbidity. It was only in the 1970s that the National Cancer Control Office organized a nationwide retrospective death survey, and obtained relatively complete and reliable statistical data on cancer mortality (Marks 1981). These results have provided a clear picture of the cancer mortality patterns and distribution characteristics in China, as reported in the Atlas of Cancer Mortality in the People's Republic of China (Li Jun-yao et al. 1979). The Atlas, besides its general scientific value, has proved to be a useful guide for cancer research and control (Li Jun-yao et al. 1981). Its statistics on mortality are important for determining priorities in the cancer control program and for more rational allocation of human and material resources. Discovery of new high-mortality areas has guided the setting up of field stations for the early detection, diagnosis, and treatment of the disease (Li Jun-yao 1980). Knowledge of the distribution of high-cancer-risk areas and population characteristics provides valuable etiologic clues for the study of causative factors and is of help for the testing of hypotheses.(ABSTRACT TRUNCATED AT 400 WORDS)