Does the use of alcohol mouthwash increase the risk of developing oral cancer?

Design Systematic review.Case selection This study had a focused research format in terms of PICO (Population, Intervention, Comparison, Outcomes). There were no age, gender or medical conditions which restricted or excluded patients from the inclusion criteria. The intervention was the use of alcohol-based mouthwashes in comparison to the control group where no mouthwash was used. A literature search was carried out utilising three electronic databases including PubMed, Scopus and Cochrane Library. The papers included for analysis within this review were all published from 2006 onwards and animal studies, case series and case reports were excluded.Data analysis The qualitative analysis included 43,499 participants from eight papers which included two meta-analyses, one clinical trial, three case-control studies and two cohort studies, all of which fulfilled the inclusion criteria. Data were analysed by two independent reviewers who initially screened the articles and removed duplications before a second round of in-depth evaluation was conducted. A third reviewer was also included to act impartially to resolve any disagreements and reduce bias within the study. Risk of bias within studies was assessed utilising the Newcastle-Ottawa Scale (NOS) which provided a uniform approach between the reviewers. A score of 6 or greater was associated with a low level of bias.Results The primary outcome parameter measured was acetaldehyde levels in saliva and the secondary outcome factor was the risk of developing an oral cancer. The results from this review concluded that the relationship between the use of alcohol mouthwash and cancer risk is complex and influenced by multiple variables. Factors which may influence the risk of developing an oral cancer from the use of alcohol mouthwash include increased frequency of rinsing (more than three times daily), total duration of mouthwash use (>35 years), poor oral hygiene and presence of other risk factors (for example, smoking and alcohol intake).Conclusions The use of alcohol-containing mouthwashes alone (when no other risk factors are present) does not increase the risk of developing an oral cancer or lead to increased salivary acetaldehyde. However, where other risk factors for oral cancer are present, the use of an alcohol-based mouthwash may further increase this risk.