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    Environmental and Injury Epidemiology and Toxicology Unit

    1100 West 49th Street
    Austin, TX 78756

    Phone: 1-800-588-1248
    Fax: 512-776-7222

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Cancer Cluster Investigations

DSHS obtains cancer incidence data from the Texas Cancer Registry, which tracks the numbers and types of new cancer cases diagnosed each year by age, race, sex, and place of residence within the State of Texas.  Cancer incidence data are generally considered to be the best indicator of cancer occurrence, and these data for Texas currently meet national standards for timeliness and data quality.

According to the National Cancer Institute, a cancer cluster is a significantly greater-than-expected number of cancer cases occurring over a specified period of time among people who live or work in the same geographical area or workplace.  DSHS follows guidelines recommended by the Centers for Disease Control and Prevention (CDC) for investigating cancer clusters.  If DSHS were to find significantly more cancer cases than expected, or if rare or unlikely cancers were to be found in unusual age groups, a number of factors would then be considered to determine whether a more in-depth study should be undertaken in an attempt to identify a likely cause.  Of the thousands of CCIs conducted annually in the United States, very few proceed to this next stage, and those that do almost invariably fail to identify a definitive cause for the apparent cluster.   

Cancer cluster investigations (CCIs) only study the rates of occurrence of new cancer cases in a particular area over time and generally only use previously collected data available from state-based cancer registries.  Consequently, they are only capable of answering the simple question, “Are there more cancer cases occurring in the area or population of concern than would be expected, based on the size and demographic characteristics of that population?”  It is important to note that CCIs cannot, and are not intended to, determine the likely cause of any of the cancers observed in the area of concern.  Likewise, they cannot be used to determine what common risk factors, specific contaminants, or exposure sources (if any) may have contributed to the observed cancer excesses (if any) in the area of concern. 

Cluster Investigations






Last updated January 28, 2015