What Is A "Cancer Cluster"?
The U.S. Centers for Disease Control and Prevention (CDC) website defines a cancer cluster as “a greater-than-expected number of cancer cases that occurs within a group of people in a geographic area over a period of time.”
The article on the CDC website notes that “the complex nature of cancer makes it inherently challenging to identify, interpret, and address cancer clusters.”
What at first appears to be a cancer cluster may not actually be one. A close examination of the information may show that the number of new cancer cases in a specified area is within a range that is considered normal or expected. Cancer cases are more likely to represent a cluster if they involve:
- One type of cancer,
- A rare type of cancer, or
- A type of cancer in a group of people not usually affected by that cancer.
An example of the third situation might be a frequent occurrence in children of a type of cancer normally seen only in adults.
To identify a cancer cluster, public health professionals develop a “case definition” which defines the population at risk, the time period involved, and type of cancer involved. Then they analyze the data and compare it with the number of cases of the cancer which could be expected in the population. CDC also advises, “Confirmation of a cancer cluster does not necessarily mean that there is any single, external cause of hazard that can be addressed.” A confirmed cancer cluster could be the result of many factors. These investigations can take years to complete, and the results may be inconclusive.
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HOW TO REPORT A SUSPECTED CANCER CLUSTER To report a suspected cancer cluster in Delaware, please call the Division of Public Health’s Cancer Program. Cancer Program staff will ask you several questions, including questions about the type or types of cancer, the number of cases of which you are aware, the community in which you suspect a cluster, and other information to help their investigation. |
For more information about cancer clusters, follow these links:
- CDC Page About Cancer Clusters
- Frequently Asked Questions from CDC
- Fact sheet on CDC Role In Investigating Clusters
- Cancer cluster fact sheet from the National Cancer Institute
- American Cancer Society page on cancer clusters
- Cancer Cluster Investigations in Delaware
- Report on 2007 Indian River, Delaware, Cancer Cluster Investigation
