Municipal Solid Waste Incineration and Risk of Soft-tissue Sarcoma: A Case-control Study

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PP-31-188 Background/Aims: Soft-tissue sarcoma is a rare neoplasia of the connective tissue with unknown etiology. Heavy metals and dioxins, which are also emitted by municipal solid waste incinerators, are among the environmental factors suspected to play a role in its etiology. We assessed the possible relation between long-term exposure to emissions of a municipal solid waste incinerator and risk of soft-tissue sarcoma in the Italian municipality of Reggio Emilia, through a population-based case-control study. Methods: We identified 50 cases of newly diagnosed sarcomas from 2001 to 2008, and we randomly selected 4 population controls for each case, matched for sex and age, of whom we geocoded residential history. We also identified 2 areas of the municipal territory with intermediate and high exposures to emissions of the solid waste incinerator. All this information was added to a Geographical Information System database, to assess exposure status of study subjects, and to calculate the associated relative risk (RR) of soft-tissue sarcoma in a conditional logistic regression model. Results: Three cases of soft-tissue sarcoma occurred among previously exposed subjects. Residence in 1 of the 2 exposed areas was associated with a RR of 0.52 (95% confidence interval [CI]: 0.12–2.37) at disease diagnosis and with a RR of 1.10 (95% CI: 0.28–4.35) 20 years before, after adjusting for educational attainment. When we limited the analysis to highly exposed subjects, we found a RR relative risk of 1.93 (95% CI: 0.32–11.71) at diagnosis and of 3.70 (95% CI: 0.72–18.97) 20 years before. No dose-response relation between exposure status and disease risk was detected. Conclusion: Overall, the risk of soft-tissue sarcoma was increased among subjects with high exposure to incinerator emissions, but risk estimates were statistically very unstable and no evidence of dose-response relation emerged. Larger studies are required to confirm a relation between emissions from waste incineration and incidence of soft-tissue sarcoma.