Opium Use and Cancer Risk: A Comprehensive Systematic Review and Meta-Analysis of Observational Studies

Abstract

Background. Epidemiological studies have reported inconsistent associations between opium use and cancer risk. We therefore conducted a systematic review and meta-analysis to investigate the relationship between opium use and cancer risk. Methods. We searched PubMed, Scopus, ISI Web of Knowledge, and Google Scholar until February 2021 and references of retrieved relevant articles for observational studies that reported the risk of cancer in relation to opium use. Random-effects models were used to calculate pooled effect sizes (ESs) as well as 95% confidence intervals (CIs) for the association between opium use and cancer risk by considering opium doses and types, duration of consumption, and routes of opium use. Results. In total, 21 observational articles, with a total sample size of 64,412 individuals and 6,658 cases of cancer, were included in this systematic review and meta-analysis. Ever opium users, compared with never opium users, had 3.53 times greater risk of overall cancer (pooled ES: 3.53, 95% CI: 2.60–4.79, P ≤ 0.01). This positive association was also seen for some individual types of cancers except for esophageal and colon cancers. Also, we found that higher opium doses and higher duration of consumption were associated with an increased risk of overall and individual types of cancer. However, the associations between opium doses and the risk of head and neck and larynx cancers were not significant. In terms of the routes of opium use, both opium ingestion and smoking were positively associated with the risk of cancer. Regarding opium types, we found that using teriak, but not shireh, could increase the risk of cancer. Conclusions. Our findings showed that opium use, particularly in the form of teriak, is a risk factor for cancer.

The carcinogenicity of opium consumption: a systematic review and meta-analysis

“…We also conducted an appraisal of the most important aspects of study quality, and documented a lack of cumulative exposure information, which might be further explored in future studies of opium consumption and cancer risk. Although other meta-analyses have been recently published on opium consumption and cancer risk [10][11][12][13][14], our systematic review is the most up to date, and has carefully considered a range of methodological sources of bias in findings, according to domains of study quality assessment defined by the IARC Monographs volume 126 Working Group.…”

“…Here, we aimed to supplement the recent qualitative IARC cancer hazard evaluation by conducting an extended systematic review and a quantitative meta-analytic assessment of the role of opium consumption and risk for selected cancers, including cancers of the urinary bladder, larynx, lung, oesophagus, stomach, and pancreas [9]. This analysis therefore represents the most comprehensive systematic review and meta-analysis to date [10][11][12][13][14]. We specifically considered in detail exposure assessment quality, and the impact of various potential methodological sources of bias and confounding on meta-analytic findings according to a registered protocol.…”

Opium alkaloids, biosynthesis, pharmacology and association with cancer occurrence

“…[ 13 ]. The analysis found that individuals who had ever used opium had a 3.53 times greater risk of developing any type of cancer, compared to those who had never used opium [ 13 ]. On the other hand, by meta-analysis investigation, the relationship between opium consumption and bladder cancer was found by studying 11 case–control, five cross-sectional and one cohort case.…”

“…In an epidemiological case-control study, Shakeri et al [99] found that an emerging esophageal cancer cell carcinoma risk factor can be opium. To evaluate the association between opium use and cancer risk, the meta-analysis review of 21 observational studies, with a combined sample size of 64 412 individuals and 6658 cases of cancer was carried out by Mansouri et al [13]. The analysis found that individuals who had ever used opium had a 3.53 times greater risk of developing any type of cancer, compared to those who had never used opium [13].…”

“…To evaluate the association between opium use and cancer risk, the meta-analysis review of 21 observational studies, with a combined sample size of 64 412 individuals and 6658 cases of cancer was carried out by Mansouri et al [13]. The analysis found that individuals who had ever used opium had a 3.53 times greater risk of developing any type of cancer, compared to those who had never used opium [13]. On the other hand, by meta-analysis investigation, the relationship between opium consumption and bladder cancer was found by studying 11 case-control, five cross-sectional and one cohort case.…”