Cancer Clusters: What Are They?

Cancer cluster is a phrase commonly used by doctors and researchers, but it’s something patients and others may not understand. This term is used to describe an occurrence where a greater than anticipated number of cancer cases occur within a defined geographic area. A cluster, for example, might be investigated when several members of the same family, neighborhood, community or workplace are diagnosed with the same or related types of cancer within a relatively short period of time.

Cancer clusters aren’t entirely common, but they can be important to identify when they occur for a few reasons. These clusters enable researchers to identity common links in cases that might enable prevention of other cases. Researchers, for example, may determine there are carcinogens in a specific environment causing the increased incidents of cancer. It may then be possible to remove these substances from the environment or otherwise mitigate human exposure.

While many possible cancer clusters are investigated, actual, true cancer clusters are fairly rare. Individuals who are concerned about a suspected cancer cluster can report their suspicions by contacting their local or state health departments. These agencies will also be able to let individuals know if an investigation into a possible cluster is already under way. The U.S. Centers for Disease Control and Prevention may be called in by state agencies should an investigation require assistance.

Cancer cluster investigations are conducted rather methodically. The first step involves gathering information about the suspected cluster, including the types of cancer involved and the number of cases. If there are a significant number of cases, an epidemiological study may be performed to determine if the increased incidents are related to environmental factors.

Cancer clusters do not occur often, but identifying them is important for helping prevent future cases. When the cause is an environmental concern, investigation may be able to reveal the source and provide a pathway for future prevention.