Alcohol cessation and cancer: Exploring the protective connection

AlcoholAndCancer: Prior to this report, what was the IARC's stance on alcohol reduction or cessation and cancer risk? 

Dr. Beatrice Lauby-Secretan: In 1987, the IARC Monographs programme first classified alcoholic beverages as carcinogenic to humans based on sufficient evidence of causality for cancers of the oral cavity, pharynx, larynx, oesophagus (squamous cell carcinoma), and liver (hepatocellular carcinoma). Subsequently, in 2007 both colorectal cancer and breast cancer were added to the list of cancer types caused by alcoholic beverage consumption, and in 2009, these conclusions were reaffirmed.

 

In 2021, the Working Group for IARC Handbooks Volume 19 on oral cancer prevention found sufficient evidence that cessation of alcohol consumption decreases the risk of oral cancer.

 

These evaluations are a scientific assessment of the body of evidence. 

​

Has this been investigated like this before?

No. There has never been a comprehensive review and evaluation of the body of scientific evidence on cessation or reduction of consumption of alcoholic beverages and the risks of each of the seven alcohol-related cancer types. Nor has there been a review and evaluation of the mechanistic evidence of alcohol reduction or cessation on reversing alcohol-related carcinogenesis.

​

Could you briefly discuss the methodology used in your report?

The IARC Handbooks follow the principle of systematic review in a rigorous, transparent process defined in the Preamble (available at https://handbooks.iarc.fr/documents-handbooks/hb-preamble-primary-prevention.pdf). Briefly, literature searches are performed by IARC, and further refined by the panel of experts based on pre-set inclusion and exclusion criteria. These experts then review and assess each study individually. The drafts are peer-reviewed by IARC and by the panel of experts over several iterations. The evaluations are based on the synthesis of the study results and study quality and the assessment of the entire body of evidence based on set criteria.

​

How does tobacco smoking interact with alcohol consumption in relation to cancer risk?

Tobacco smoking also causes cancer at those sites affected by alcohol consumption. There is a strong interaction between tobacco smoking and alcohol consumption, so that the risk of cancer for most sites is larger than the sum of the risk from tobacco smoking plus the risk from alcohol consumption. This interaction has been clearly explained at the molecular level.

​

You found different evidence for different cancers. What were the key findings regarding alcohol cessation and the risk of oral and esophageal cancers?

Based on the evidence reviewed from relevant studies published to date, the Working Group concluded that there is sufficient evidence that, compared with continuing consumption, reduction or cessation of alcoholic beverage consumption reduces the risk of oral cancer and oesophageal cancer. The Working Group also concluded that there is sufficient evidence from mechanistic studies that cessation of alcohol consumption reduces alcohol-related carcinogenesis.

​

What about other cancers, such as laryngeal, breast and colorectal cancers?

First, it is important to remember that this was a review and evaluation of existing studies, and the evaluations are constrained by the number of studies available for review. 

 

The evidence that reduction or cessation of alcoholic beverage consumption reduces cancer risk was limited for laryngeal, breast and colorectal cancers. 

 

For laryngeal cancer, research is needed to better disentangle the potential reduction in risk due to reduction or cessation of alcohol consumption from that due to smoking cessation.

 

For breast cancer, it is possible that any reduction in risk due to reduction or cessation of alcohol consumption may be limited to hormone receptor-positive breast cancers, which are more strongly related to alcohol consumption. However, few studies assessed reduction or cessation of alcohol consumption and risk by hormone receptor subtype. Therefore, more research is needed to better understand potential differences in risk reduction associated with alcohol reduction or cessation among breast cancers stratified on hormone receptor status, or other molecular subtypes.

 

For colorectal cancer, the Working Group concluded that the current body of evidence was limited because of the inconsistencies among studies of reduction of alcohol consumption and the few studies on duration of cessation of alcohol consumption. 

​

Did your research identify any gaps in the current understanding of alcohol consumption and cancer risk?

Most importantly, further research is needed to better understand the duration of alcohol cessation and the amount of alcohol reduction needed to observe a reduced risk compared to continuing consumption, for example. 

​

What implications might this study have for public health policies on alcohol consumption?

The Working Group’s conclusion that there is sufficient evidence that, compared with continuing consumption, reduction or cessation of alcoholic beverage consumption reduces the risk of oral cancer and oesophageal cancer, may be useful to national and international health agencies to develop evidence-based interventions, guidelines, and recommendations for reducing cancer risk, and thus will contribute to efforts to increase awareness of the link between alcohol consumption and cancer risk.

​

How should this report’s findings be communicated to patients and the public? 

It is important to add that alcoholic beverage consumption is a major public health concern, and for cancer specifically, in 2020 an estimated 741 300 new cancer cases (4.1% of all new cancer cases) were attributable to alcoholic beverage consumption worldwide.

 

All types of alcoholic beverages, including beer, wine and spirits, are linked to cancer. Research shows that even low amounts of alcohol consumption increase the risk breast and other types of cancer including oral, pharyngeal and oesophageal cancer. 

​

​

Find more details of IARC´s findings