Occupational arsenic exposure and genitourinary cancer: Systematic review and meta-analysis

Background: Existing evidence suggests that ingestion of high doses of arsenic through drinking water is associated with an increased risk of genitourinary cancers, while systematic evidence on workers exposed to arsenic is lacking. Aims: The aim of this study is to systematically review the evidence on the association between occupational exposure to arsenic and genitourinary cancer risk and mortality. Methods: A systematic literature search was carried out on Pubmed, Web of Science and Embase by including cohort and case-control studies. Study-specific relative risks (RRs) and the corresponding 95% confidence intervals (CIs) were pooled using Mandel-Paule random-effects model. Contour-enhanced funnel plot and Egger's test were used to assess the occurrence of publication bias. Results: A total of 17 studies were included in the meta-analysis, 7 on cancer incidence (n = 161,244 individuals) and 10 on cancer mortality (n = 91,868). Most of them were cohort (71%) and industry-based studies (59%). The meta-analysis failed to detect an increased risk of genitourinary cancers among workers exposed to arsenic, except for a suggestive but not significant positive association for bladder cancer incidence (RR: 1.26, 95% CI: 0.89, 1.80), although this estimate was based on only three studies. No compelling evidence of publication bias was found (P = 0.885). Conclusions: Our findings did not show an association between occupational exposure to arsenic and genitourinary cancers, although further high-quality studies with detailed exposure assessment at the individual level are needed to clarify this relationship.