Workers engaged in the production of Portland cement may come into contact with potential occupational hazards, but existing epidemiological studies show wide variation in risk estimates for cancer incidence and mortality in relation to cement exposure. This report identified studies of cement workers and associations with cancer incidence and mortality in a systematic review and meta-analysis. A systematic review according to the PRISMA guidelines was conducted to identify studies of Portland cement workers and cancer outcomes. Meta-analyses were performed using random effects models for all cancers combined and for each cancer site with three or more reported measures of risk. A total of 26 studies were included in the review (14 occupational cohort studies and 12 case-control studies). Overall, the meta-relative risks did not provide convincing evidence for increased risks of any cancers in relation to cement exposure. Meta-SMR and 95% CIs were 0.94 (0.76 to 1.16) for six studies reporting all cancers combined, 0.93 (0.62 to 1.39) for seven studies reporting on lung cancer, 1.07 (0.72 to 1.59) for five studies reporting on stomach cancer, and 1.05 (0.79 to 1.40) for four studies reporting on colorectal cancer. Meta-relative risks for cancer incidence were similarly null for all sites with the exception of colorectal cancer which had a borderline statistically significant elevated risk (SIR=1.38, 95% CI 1.02 to 1.88). Overall, the meta-relative risks calculated across 26 published studies do not provide evidence of increased risks for cancer in relation to cement exposure.
EpidStat in the News
EpidStat presented "Survival Synthesis: Methods for Meta-analysis of Survival Rates and Aggregation of Survival Data" at a poster session for the International Conference on Health Policy Statistics on January 10, 2018 in Charlston, SC. The poster details the methods used in Bylsma et al. Arteriovenous Fistulae for Haemodialysis: A Systematic Review and Metaanalysis of Efficacy and Safety Outcomes. European Journal of Vascular and Endovascular Surgery, 2017. We discussed the process of digitizing survival curves from the published literature and simulating individual patient data to derive survival statistics that were not published with the article. We conclude that while labor-intensive, the methodology makes the best use of available study data.
EpidStat presented "Prevalence of KRAS and BRAF Mutations in Metastatic Colorectal Cancer (mCRC) by Tumor Location: A Review and Meta-analysis" on January 20, 2018 at the ASCO Gastrointestinal Cancers Symposium. Results from 44 studies comprising nearly 16,000 mCRC patients demonstrated that both KRAS and BRAF mutations were significantly more prevalent among right-sided colon tumors than left-sided tumors. These results may aid clinicians and researchers in the search for target novel therapeutics.