Soft-tissue sarcoma and non-Hodgkin's lymphoma clusters around a municipalsolid waste incinerator with high dioxin emission levels

Overall evidence from epidemiologic studies in the workplace suggests that dioxin is a human carcinogen, but whether low doses affect the general popu lation remains to be determined. The authors examined the spatial distribut ion of soft-tissue sarcomas and non-Hodgkin's lymphomas around a French mun icipal solid waste incinerator with high emission levels of dioxin (16.3 ng international toxic equivalency factor/m(3)). Not consistently associated with dioxin exposure, Hodgkin's disease served as the control cancer catego ry. Clusters were identified from 1980 to 1995 in the area ("departement") of Doubs by applying a spatial scan statistic to 26 electoral wards. The mo st likely and highly significant clusters found were identical for soft-tis sue sarcomas and non-Hodgkin's lymphomas and included the area around the m unicipal solid waste incinerator; standardized incidence ratios were 1.44 ( observed number of cases = 45, focused test p value = 0.004) and 1.27 (obse rved number of cases = 286, focused test p value = 0.00003), respectively. Conversely, Hodgkin's disease exhibited no specific spatial distribution. C onfounding by socioeconomic status, urbanization, or patterns of medical re ferral seemed unlikely to explain the clusters. Although consistent, these findings should be confirmed by further investigation (e.g., a case-control study in which dioxins are measured in biologic tissues) before clusters o f soft-tissue sarcoma and non-Hodgkin's lymphoma are ascribed to dioxin rel eased by the municipal solid waste incinerator.