The case-control study in Kansas reported by Hoar et al1 in this issue has importance beyond its population of agriculture workers to the highly controversial and adversarial issue of health effects associated with herbicide exposure in Vietnam. The well-designed and carefully executed Kansas study adds substantially to the cumulating body of evidence concerning the following question: Does human exposure to phenoxyacetic acid herbicides increase the risk of soft-tissue sarcomas (STS), Hodgkin's disease (HD), and non-Hodgkin's lymphoma (NHL)? The findings among Kansas farmers are in accord with "no" answers to the first two malignancies and a "yes" answer to the third.
Most relevant to the Kansas study are the series of case-control investigations undertaken by Hardell and colleagues2-4 in rural Sweden in the mid- and late 1970s. Hardell's studies found highly significant relative risks, of magnitude fivefold and sixfold, for exposure to phenoxyacid herbicides in association with STS, HD,
Colton T. Herbicide Exposure and Cancer. JAMA. 1986;256(9):1176-1178. doi:10.1001/jama.1986.03380090116029