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Cancer Cluster Investigations

Environmental Epidemiology and Toxicology (EET) colloborates with the Colorado Central Cancer Registry in response to concerns about possible cancer clusters thought to be related to environmental risks.


What is a cancer cluster?

A cancer cluster is defined as a greater-than-expected number of cancer cases that occurs within a group of people in a geographic area over a specific period of time.


How is a cancer cluster investigated?

The Centers for Disease Control and prevention (CDC) develops and distributes general guidelines for states to use when determining if an excess number of cancers have occurred. If a suspected cancer cluster has been identified, EET then considers whether the cancer cases can plausibly be linked to some shared environmental exposure. EET explores possible environmental risks in the area of concern and determines what types of cancer might be related to suspected environmental risks. 


Data routinely collected by the state Cancer Registry under Colorado law and Board of Health regulation provide an important tool to respond to community and occupational concerns about rates of cancer in their neighborhood or workplace. All cancers diagnosed in Colorado are reported to the Cancer Registry with the exception of non-melanoma skin cancers. Registry data allows rapid response to evaluation of exposure-disease relationships and allows public health officials to investigate whether cancer is occurring in numbers that are significantly higher than background rates. 


It is important to note that cancer is a common disease and can be found among many people in any given geographic area. In the United States, one in two men and one in three women will develop cancer over the course of their lifetime. These figures show the unfortunate reality that cancer occurs more often than many people realize.



Rocky Mountain Arsenal


Lookout Mountain 2004 Update of Tumor Incidence


Vasquez Boulevard / I-70 Cancer Study



Environmental Epidemiology and Toxicology: 303-692-2700