General survey of intertumor linkages that connect the chronological changes of age-adjusted incidence rates of 13 neoplasia types from l975 to l993 in Japan.

We attempted a stochastic study of cancer risk change in time using the follow-up data of the age-adjusted incidence rate (AAIR) of cancer in Japan, which covered 13 neoplasia types of both sexes in scope, and ranged from 1975 to 1993 in time. The purpose of our study was to test whether or not there was any mathematical regularity that was to condition cancer risk changes in time in all the 13 human neoplasia types. We investigated the relation between 2 neoplasias as regards log AAIR changes in time by the direct successive elimination method of Gauss, a fitness test of a given pair data to an equilibrium model.