Clustering of esophageal cancer among white men in the United States.

Abstract

Studies of the geographic distribution of esophageal cancer in the United States have been limited. We aimed to examine geographic clustering of esophageal cancer in the United States and assess whether that clustering is explained by the distribution of known risk factors for esophageal cancer. We conducted cluster analyses derived from county mortality rates of esophageal cancer, using publicly available datasets. State incidence rates of esophageal adenocarcinoma were from the National Program of Cancer Registries, and county esophageal-cancer mortality rates were from the Vital Statistics Cooperative Program. County prevalences of cigarette use, alcohol use, obesity, education, and income were published estimates derived from the Behavioral Risk Factor Surveillance System and the American Community Survey. The primary outcomes were clusters of high and low esophageal-cancer mortality rates among non-Hispanic white men, both unadjusted and adjusted for risk factors. Age-standardized county rates of esophageal-cancer mortality among non-Hispanic white men ranged from 4.8 to 21.2 per 100,000/year. There was a cluster of high mortality in the Great Lakes states and New England and a cluster of low mortality in the Southeastern United States. State incidence rates of esophageal adenocarcinoma were consistent with this pattern. Adjusting for risk factors did little to change the pattern of observed rates or the clusters derived from them. Among non-Hispanic white men, there are clusters of high and low mortality rates with esophageal cancer within the United States, likely representing esophageal adenocarcinoma; but those clusters were not explained by several known risk factors. Focusing future efforts in the high-cluster areas might improve the efficiency of cancer screening and control.