Exposure to municipal solid waste incinerators and cancer risk in surrounding populations: A systematic review and meta-analysis.

Evidence on the carcinogenic effects of municipal solid waste incinerators (MSWI) is inconsistent. This meta-analysis assessed associations between exposure to MSWI emissions and cancer risk. PubMed, Scopus, and Web of Science were searched for ecological, case-control, or cohort studies, evaluating cancer-related outcomes in populations exposed to MSWI. Study quality was evaluated. Random-effects meta-analyses were performed when at least three studies reported the same cancer outcome. Heterogeneity was assessed using I² and robustness with leave-one-out sensitivity analyses. Nineteen studies (11 ecological, 4 cohort, 4 case-control; 1996-January 2025) were included. Most ecological studies had poor quality, while cohort and case-control designs were fair-good. Meta-analyses showed modest excess risks for non-Hodgkin lymphoma incidence and lung cancer mortality, with a low certainty of evidence. For other cancers, no consistent and clear associations were found. Overall, current evidence is uncertain to establish causal links between MSWI exposure and cancer. The predominance of ecological designs, limitations in exposure assessment, and methodological heterogeneity contribute to this imprecision.