On the problem of gastric carcinoma cluster determination

In the present study the author describes a method for the determination of a limited area (group of population) for carrying out epidemiological investigations into the occurrence of gastric cancer. The area thus determined is referred to as a focus or a cluster of gastric carcinoma occurrence. These clusters are derived from the comparison of the minimum population number (N-) in which there may develop, with 99% probability, kappa cases of gastric cancer at the given incidence rate, with the actual population number. All the necessary calculations were made using specially designed tables. If the actual population (with a rural Soviet) taken as a territorial unit) was less than N- at kappa cases of the disease, the author concludes that the occurrence of the given number of the disease cases at the corresponding Soviet exceeds the limit of chance and that in such a case it would be justified to undertake detailed analytical epidemiological investigations to review the hypotheses as to the genesis of gastric carcinoma.