Responding to concerns raised last year about a potential "cancer cluster" involving children diagnosed with leukemia in Grand Forks County, officials from the North Dakota Health Department and the Statewide Cancer Registry plan to meet next month with parents of the children.
The families and child advocates had identified at least nine cases of children diagnosed with some form of leukemia in the previous three years, including seven in the city of Grand Forks. Two of the children had died; the rest were in treatment or in remission.
After Grand Forks residents raised concerns last year, state health officials analyzed 10 years of county health records to determine whether they could find any worrisome patterns.
"While the rates (of childhood cancer) between 1997 and 2006 were comparable to the rest of the state and the U.S., the numbers for the year 2007 were higher than expected," epidemiologist Alice Musumba wrote to the families.
She said that she and the director of the Statewide Cancer Registry "would like to meet with each family" in early to mid-July. As of Monday, she had received "very positive responses" from two of the families.
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"Although this apparent increase could be by chance, it could also be due to a number of factors that we would need to investigate," she wrote. "To help us understand what might have caused the increase, we would like to meet with you and explore (whether) some common factors exist between your children and other children in the county.
"If common risk factors are found, we may need to test them in a formal investigation study."
The National Cancer Institute defines a disease cluster as "the occurrence of a greater than expected number of cases of a particular disease within a group of people, a geographic area, or a period of time."
The Centers for Disease Control and Prevention defines a cluster investigation as "a review of an unusual number, real or perceived, of health events (for example, reports of cancer) grouped together in time and location."
Some causal relationships, such as the link between smoking and lung cancer, have been well established. But while air, soil and water quality remain sources of great public concern, "few community-level environmental exposures have been well studied," according to the CDC's National Environmental Public Health Tracking Network.
It was the discovery of an unusually high number of cases of a rare type of pneumonia among homosexual men in the early 1980s that led eventually to identification of the human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS).
One of the best known examples of a cancer cluster emerged in the 1960s, when doctors reported many cases of mesothelioma, a rare cancer of the lining of the chest and abdomen. Researchers found exposure to asbestos the likely shared risk factor.
Haga is a reporter for the Grand Forks Herald
