The Centers for Disease Control and Prevention (CDC) continues to be aware of the need for response to public concern as well as to state and local agency concern about cancer clusters. In 1990 the CDC published the "Guidelines for Investigating Clusters of Health Events," in which a four-stage process was presented. This document has provided a framework that most state health departments have adopted, with modifications pertaining to their specific situations, available resources, and philosophy concerning disease clusters. The purpose of this present article is not to revise the CDC guidelines; they retain their original usefulness and validity. However, in the past 15 years, multiple cluster studies as well as scientific and technologic developments have affected cluster science and response (improvements in cancer registries, a federal initiative in environmental public health tracking, refinement of biomarker technology, cluster identification using geographic information systems software, and the emergence of the Internet). Thus, we offer an addendum for use with the original document. Currently, to address both the needs of state health departments as well as public concern, the CDC now a) provides a centralized, coordinated response system for cancer cluster inquiries, b) supports an electronic cancer cluster listserver, c) maintains an informative web page, and d) provides support to states, ranging from laboratory analysis to epidemiologic assistance and expertise. Response to cancer clusters is appropriate public health action, and the CDC will continue to provide assistance, facilitate communication among states, and foster the development of new approaches in cluster science. Key words: cancer, cancer clusters, Centers for Disease Control and Prevention, environmental hazards, epidemiologic cluster investigations, state health departments. Environ Health Perspect 115:165-171 (2007). doi:10.1289/ehp.9021 available via http://dx.doi.org/ [Online 30 November 2006]
Disease clusters continue to concern the public, and public sentiment that environmental causes are responsible and must be investigated is widely prevalent. More than a decade ago, the Centers for Disease Control and Prevention (CDC) recognized the need to develop operating procedures for response to public concern about disease clusters. The National Conference on Clustering of Health Events was held 15-16 February 1989 in Atlanta, Georgia; the proceedings were published (Rothenberg et al. 1990a); and the CDC released the "Guidelines for Investigating Clusters of Health Events" (CDC 1990) in which a four-stage process was presented: a) an initial response to gather source information, b) an assessment of the occurrence of the health event, c) a feasibility study, and d) an epidemiologic investigation. During the last 15 years, these guidelines have provided a framework that most state health departments have adopted, modifying it for their specific situations and available resources. The states have the primary responsibility for response to cancer cluster concerns within their domain. The CDC guidelines emphasize the need for health agencies to develop an approach that maintains community relations while responding to clusters efficiently; the approaches vary among states as well as according to the nature of the cluster and the availability of case and comparison data. The orientation of each state-based inquiry response and investigation plan is shaped by state philosophy and experience with previous clusters.
The purpose of this article is not to revise the CDC guidelines; they retain their usefulness and validity. However, in the past 15 years, numerous cluster studies [Agency for Toxic Substances and Disease Registry (ATSDR) 2006; Cochise County Health Department (CCHD) 2005; Heath 2005; Massachusetts Department of Public Health (MDPH) 2005; National Cancer Institute (NCI) 2005; New Jersey Department of …