Occupational benzene exposure and hepatobiliary and pancreatic cancers: a systematic review and meta-analysis

Evidence on the association between benzene and hepatobiliary and pancreatic cancers is scarce. Hence, we aimed to summarize current literature on the association between occupational benzene exposure and these cancers. We conducted a systematic review and meta-analysis by searching Pubmed, Embase, and Scopus through April 2024 to identify cohort and nested case-control studies. We evaluated study quality with Newcastle-Ottawa Scale and estimated pooled relative risks (RRs) and 95% confidence intervals (CIs) using Paule-Mandel method. Twenty-nine studies were included in the meta-analysis. Occupational benzene exposure was associated with hepatobiliary cancer incidence (RR: 1.14; 95% CI: 1.04-1.24; I2=0.0%, p=0.707), but not with mortality (RR: 0.89; 95% CI: 0.69-1.15; I2=66.7%, p<0.001). Pooled RRs for incidence and mortality were 1.13 (95% CI: 0.93-1.36; I2=0.0%, p=0.729) and 0.79 (95% CI: 0.65-0.96; I2=0.0%, p=0.539) for liver cancer, 1.16 (95 % CI: 0.73-1.82; I2=34.6%, p=0.164) and 2.00 (95% CI: 0.96-4.19; I2=67.7%, p=0.015) for gallbladder cancer, and 0.95 (95% CI: 0.78-1.16; I2=13.5%, p=0.316) and 1.00 (95% CI: 0.87-1.14; I2=29.6%, p=0.100) for pancreatic cancer, respectively. Occupational benzene exposure might be associated with hepatobiliary cancer. Further studies, with detailed exposure assessment and control for potential confounders, are needed to clarify this relationship.