“Mouthwash ‘can cause oral cancer,’” reported The Daily Telegraph today. The newspaper said that researchers have claimed there is now ‘sufficient evidence’ that
“Mouthwash ‘can cause oral cancer,’” reported The Daily Telegraph today. The newspaper said that researchers have claimed there is now ‘sufficient evidence’ that mouthwash containing alcohol contributes to an increased risk of the disease. The newspaper said the claims follow a review of the latest studies, with the authors suggesting that mouthwash should be “taken off supermarket shelves and labelled with health warnings”.
The authors of this review have presented their own subjective opinion about the evidence for harms associated with alcohol-based mouthwash. Importantly, they highlight the fact that some studies have found no link between these mouthwashes and oral cancer. This confirms a difference of opinion that will require further investigation.
Given that alcohol consumption has been linked to an increased risk of oral cancer, it is important that more research is carried out using systematic, robust methods.
Drs MJ McCullough and CS Farah carried out this study. It is unclear whether any external funding was received. The study was published in the peer-reviewed medical journal, the Australian Dental Journal.
The publication is a non-systematic, narrative review of the evidence linking mouth cancer with the use of alcohol-based mouthwashes. It also discusses the results from laboratory and animal studies. The authors put forward mechanisms for a possible increase in risk before making their subjective conclusions about the balance of evidence.
The authors begin by discussing the worldwide incidence of oral cancer and current survival rates. They list long-established risk factors for the development of oral cancer, including smoking, alcohol consumption and chewing tobacco, as well as other suspected factors, such as viruses, diet and poor oral hygiene.
The researchers then go on to discuss some of the evidence, including epidemiological (population) studies, which have found a link between drinking alcohol and mouth cancer. They discuss several laboratory and animal studies that have investigated the effects of alcohol on cells and tissues in cultures and in animals. Based on this, the researchers put forward a proposed mechanism for the possible effects.
The researchers then talk about studies that have looked specifically at the effects of alcohol-based mouthwashes on oral health in humans. They say that, while some case-control studies have found an association between alcohol-based mouthwashes and oral cancer, others have not. They focus on the results of a recent and large case-control study in 6,000 people (3,200 with head and neck cancers and 2,752 controls), which found that the use of mouthwash increased the odds of oral cancer by nine times in current smokers. They do not provide results for non-smokers or former smokers.
The researchers say that on the basis of their review, they “believe that that there is now sufficient evidence to accept the proposition that alcohol-containing mouthwashes contribute to the increased risk of development of oral cancer”. They also say that they believe that healthcare professionals should not recommend the long-term use of alcohol-based mouthwashes.
This narrative review collected research on alcohol consumption, along with the use of alcohol-based mouthwashes and oral cancer. The review then discussed the possible ways that these may increase risk of the disease.
There are several points to highlight:
Given that drinking alcohol is the second most important risk factor for oral cancer (source: Cancer Research UK), this is an important discussion, and more research into this is needed.