Anthraquinone laxatives use and colorectal cancer: A systematic review and meta-analysis of observational studies.

This systematic review and meta-analysis were conducted to determine the effects of anthraquinone (AQ) laxatives on colorectal cancer (CRC). We searched PubMed, Embase, Google Scholar, and CENTRAL from inception until March 2021, for randomized controlled trials (RCTs) and observational studies. Through the systematic review, we identified 8 observational studies evaluating AQ laxatives use as a risk factor for CRC development, and 5 studies on CRC risk were included in the meta-analysis using a random-effects model. Through the meta-analysis, we found that a history of AQ laxatives use compared with "other" and "no laxatives" use was associated with CRC development (OR: 1.41; 95% CI: 0.94-2.11), although not at a statistically significant level. The possible association persists even after removal of the outlier studies (OR: 1.51; 95% CI: 0.97-2.34). Selection of cases and controls was judged at low or unclear risk of bias across almost all studies, and the quality of evidence was from moderate to low. In conclusion, it is not possible to associate the use of AQ laxatives with the development of CRC. However, the trend toward an increased risk of CRC provides a strong indication for investigating this issue by performing further high-quality studies.

Association between anthraquinone laxatives and colorectal cancer: protocol for a systematic review and meta-analysis.

INTRODUCTION: Products containing anthraquinones (AQ) are mainly used as laxatives and have several biological effects. Long-term use of AQ laxatives is associated with an increased risk of serious adverse events (AEs), such as colorectal cancer (CRC). We will systematically synthesize the evidence on the potential association between the use of AQ laxatives and the risk of CRC. METHODS AND ANALYSIS: We will search MEDLINE, Embase, Scopus, the Cochrane Library, Google Scholar, and Clinicaltrials.gov. To avoid missing any relevant studies, we will search the bibliographies of retrieved papers and recent reviews in the field. Interventions will include products containing oral AQ laxatives, in particular, those derived from rhubarb, senna, cascara, buckhorn, and aloe. Two review authors will independently screen title, abstract, and full texts and will independently extract data from included studies. The primary outcome is the number of participants diagnosed with CRC, while the secondary outcome will be cases of melanosis coli. We will also consider all other AEs reported in the included studies, in particular, intestinal bleeding, alterations of gastrointestinal motility, and potential for dependence. When possible and appropriate, for each outcome, a meta-analysis will be performed. DISCUSSION: This protocol is prepared in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. The protocol gives an insight into the scope and parameters for the systematic review to be carried out. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019125414.