Abstract
A23
Introduction. Recently, the media in Australia have reported instances of apparently high incidences of cancer amongst groups of individuals who work in the same building and have similar jobs. Such instances include staff a broadcasting authority, a major art gallery, a hospital, and two separate higher education facilities. In developed countries, large numbers of perceived cancer clusters are reported to health authorities, but only a minority merit close investigation. Community concern might be allayed, and productive investigations facilitated, if criteria were available for an immediate ad hoc evaluation of putative clusters >Methods Cluster investigations (1,2) generally have two aspects. Determination of whether a greater-than-expected incidence of disease is evident and evaluation of agents considered capable of accounting for the cluster on the basis of (a) recognized carcinogenicity and (b) relevant exposure. Current and previously investigated clusters have been assessed with reference to these approaches to determine whether they can provide initial indicators of clusters warranting close examination. >Results. Characteristics of multiple cancer clusters investigated in Australia during the past two years have been reviewed. Determination of greater-than-expected incidence is inherently challenging, with the criteria for specifying the cluster being subjective rather than objective. In clusters deemed to warrant investigation, certain characteristics of the cases may be used to flag circumstances that are cause for concern. These include commonality of tumour type, relatively rarity of tumour type and age of persons affected. Investigation of relevant carcinogens must involve both agents exhibiting requisite biological activity as well as agents perceived by those affected as being of concern (3). If neither category serves to implicate a causative agent(s), the likelihood of a productive investigation is minimal. >Discussion. Cancer clusters have had made a minor contribution to the identification of novel carcinogens, but the perception of a cluster often generates widespread community concern. Criteria for the evaluation of putative cancer clusters can be specified in lay terms. Usage of these criteria may reduce community apprehension regarding ill-defined hazards and focus attention on the most productive avenues of investigation. Availability of criteria on relevant websites may reduce initial concern and also reduce the number of notifications to health authorities. >(1) Westley-Wise VJ, Stewart BW, et al Investigation of a cluster of leukaemia in the Illawarra region of NSW, 1989-1996. Med J Aust 171: 178-173, 1999. >(2) Thun MJ, Sinks T. Understanding cancer clusters. CA Cancer J Clin 54: 273-80, 2004.(3) Stewart BW. “There will be no more!”: the legacy of the Toowong breast cancer cluster. Med J Aust 187: 178-180, 2007.
Sixth AACR International Conference on Frontiers in Cancer Prevention Research-- Dec 5-8, 2007; Philadelphia, PA