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Cancer Cluster Information

Guidelines for Examining Unusual Patterns of Cancer and Environmental Concerns

In general, state, tribal, local, and territorial health departments play the primary role in examining unusual patterns of cancer in communities, including those associated with local environmental concerns. CDC/ATSDR provides scientific guidance to health departments related to environmental health concerns and unusual patterns of cancer.

CDC/ATSDR has released an updated guidance document, Guidelines for Examining Unusual Patterns of Cancer and Environmental Concerns, to help health departments as they investigate patterns of disease in communities. This document updates the 2013 MMWR article: “Investigating Suspected Cancer Clusters and Responding to Community Concerns: Guidelines from CDC and the Council of State and Territorial Epidemiologists.”

Notable enhancements to the guidelines include the following:

  • Expanding the name of the guidance document to include examining patterns of cancer and environmental concerns
  • Revising the definition of a cancer cluster and introducing the concept of “unusual patterns of cancer” to describe situations that may warrant further assessment
  • Including specific and standardized approaches to better engage community advocates
  • Providing a standardized template to better document the nature and extent of cancer and environmental concerns
  • Updating approaches to identify and investigate unusual patterns of cancer, including the suggestion for proactive evaluation and routine monitoring
  • Suggesting what information to share with CDC/ATSDR
  • Enhancing appendices describing statistical and geospatial methods supporting the evaluation of unusual patterns of cancer

While the revised guidance includes new methods to better engage with community members and advocates, statistical and other scientific challenges may make it difficult to directly associate factors that may play a role in the cause(s) of unusual patterns of cancer. Although limitations and challenges remain, the revised guidelines propose an approach to identifying and investigating unusual patterns of cancer as part of routine surveillance activities as well as new criteria and decision trees for responding to cancer and environmental concerns.

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