SURVEILLANCE OF CLUSTERING NEAR POINT SOURCES

Health authorities are often alerted to suspected cancer clusters near the vicinity of potential point sources by members of the public. A s urveillance system, where administrative regions around the potential point sources are regularly monitored for high disease rates, would al low for responses which are easier to obtain, timelier, and less expen sive than individual thorough investigations. The monitoring could be done by using the so-called 'focused' tests for detecting disease clus tering. However, these tests, generally designed to detect clusters of a fixed size around the foci are not particularly effective when deal ing with administrative regions with substantial differences in popula tions. In this work, an approach which overcomes the problem to a cert ain extent is described Here the selected cluster sizes are based on t he populations of the administrative regions under examination. The ap proach is used to investigate whether cancer clustering appears in the vicinity of the pulp and paper mills in British Columbia for the year s 1983-1989. The results indicate that the approach performs reasonabl y well in identifying cancer sites for which elevated risks have also been suggested in the epidemiologic literature. Consequently, this met hodology could be utilized to provide guidance for further investigati on even in the absence of local reports. Similarly, it could be readil y utilized to provide timely responses to local reports.