Concerned individuals may report a suspected cancer cluster to their local health department. The local health department will refer the caller to the state health department, if necessary. Local and state health departments use established criteria in investigating reports of cancer clusters. Although health departments may use different processes, most follow a basic procedure in which increasingly specific information is obtained and analyzed in stages. Health departments are likely to request the following:
Information about the potential cluster: type(s) of cancer, number of cases, suspected exposure(s), and suspected geographic area/time period.
Information about each person with cancer in the potential cluster: name, address, telephone number, gender, race, age, and area(s) lived in/length of time.
Information about each case of cancer: type of cancer, date of diagnosis, age at diagnosis, metastatic sites, date of death (if applicable), and physician contact.
Information about risk factor for each diagnosed person including smoking habits, family history of cancer, occupation(s), and diet.
Most states currently have central registries that collect data on cancer incidence (the number of new cancer cases reported). The data in these registries can be used to compare expected cancer rates in certain categories, such as a geographic area, age, or racial group, with rates reported in a suspected cancer cluster to determine whether there is a true excess of cases.
* Reference: National Cancer Institute, August 2000