Over the years, the New York Times and writers associated with it have done more than most of us to debunk scares over purported cancer clusters. “When multiple cases of cancer occur in a community, especially among children, it is only human to fear a common cause,” wrote George Johnson in a 2015 Times piece. “Most often these cancer clusters turn out to be statistical illusions, the result of what epidemiologists call the Texas sharpshooter fallacy. (Blast the side of a barn with a random spray of buckshot and then draw a circle around one of the clusters: It’s a bull’s-eye.)”
Johnson’s writings in publications other than the Times have cogently analyzed dubious claims of cancer clusters in Toms River, N.J. and Love Canal, N.Y. Times science reporter Gina Kolata was a pioneer in questioning claimed incidence patterns, and a Times editorial helped in dispelling one of the most famous cancer cluster theories, that of breast cancer on Long Island.
Dozens of refuted cancer cluster scares later, are we more cautious when new ones are put forward? Or has nothing changed?
On Jan. 2 the Times published, to predictably sensational reaction, a piece by Hiroko Tabuchi profiling a claimed childhood cancer cluster in Johnson County, Indiana. Local campaigners have collected cases of childhood cancers — diverse kinds of it, not all one type — associated with the county since 2008, which would imply a rate of six cases per year. The piece, unfortunately, omits to mention the county’s population; it’s 139,654. It does concede, somewhat backhandedly, that the county is within a broadly normal range on its numbers, by noting that it has an incidence of childhood cancer slightly above the average for American counties, placing it in the 80th percentile of all such counties, which in this kind of statistical distribution means not really any great outlier at all.
Cluster alarms call for a culprit, and the local campaigners have settled on a now-shuttered industrial plant that used TCE (trichloroethylene), a solvent familiar from dry cleaning and used at many thousands of sites. They suspect it may have spread through the water and subsequent evaporation, which would explain — or would it? — which some sick children lived in homes distant from the plant and why current water testing is at best inconclusive.
I’ve written a fair bit about cluster controversies in the past, including the one in Hinkley, Calif. made famous by Erin Brockovich, and the Woburn, Mass. story captured in the book and movie “A Civil Action.”