Uncovering the Link Between Alcohol and Cancer: An Interview with Harriet Rumgay

Lauri Beekmann, NordAN: Could we start with a personal note? What brought you to focus on alcohol and cancer link?

Harriet Rumgay: I am a strong advocate for cancer prevention and I previously worked on a study estimating the impact of 14 modifiable risk factors, including alcohol use, on the burden of cancer in the UK. Through this study, and my work at Cancer Research UK (where I worked at the time), I learnt more about the public health importance of major risk factors for cancer. Specifically for alcohol, I learnt that the causal link between alcohol and cancer is often unknown or overlooked among the public and policy-makers, and that progress in alcohol control had stalled in many regions. I believed that we needed new and updated evidence on alcohol and cancer to bring focus to the fact that alcohol is a major risk factor for cancer and that more needs to be done at a policy level to reduce the harms caused by alcohol.

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Your thesis focused on the global level. How significant is alcohol's role in cancer risk?

The effects of alcohol on cancer risk have been studied for many decades. Alcohol and its toxic metabolite acetaldehyde can drive cancer development through several complex pathways that are often interlinked. More than 30 years ago (in 1988), the International Agency for Research on Cancer (IARC) Monographs program classified alcoholic beverages as a group 1 carcinogen, the same category as tobacco and asbestos, based on epidemiological and biological evidence. So we've known for more than 30 years that alcohol causes cancer, and scientific evidence has confirmed that alcohol increases the risk of at least seven different cancer types.

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In our global study at IARC we found that alcohol causes a substantial burden of cancer globally and we estimated that more than 740 000 cases of cancer in 2020 were caused by drinking alcohol. This was the equivalent of 4% of cancer cases or more than 2000 cases per day.

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The official statement is that "alcohol causes at least 7 different cancers". What is the status of these other cancers that we are not 100% sure we should add to these 7?

Drinking alcohol can increase the risk of at least seven different cancer types, including cancers of the mouth, throat, larynx, oesophagus, liver, colorectum, and breast. Two cancer types which have emerging evidence of a causal link with alcohol are pancreatic cancer and stomach cancer. Currently, IARC and the World Cancer Research Fund (WCRF) have not been able to conclude whether alcohol increases the risk of pancreatic cancer and stomach cancer due to limited evidence, but this limited evidence suggests that heavy drinking of at least four or five drinks per day could increase the risk of pancreatic and stomach cancers.

 

In our global study at IARC, we tested what would happen to the potential burden of cancer caused by alcohol if pancreatic and stomach cancers were included in our estimates, and we found that the potential burden of cancer caused by alcohol increased to more than 800,000 cases globally in 2020, or 4.5% of all cancer cases, due to an additional 60,000 cases of pancreatic cancer or stomach cancer worldwide.

 

The relationship between alcohol and other cancer types including prostate cancer, lung cancer, and skin cancer is still being studied and there isn't enough evidence to confirm whether there is a causal link yet.

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One of the main findings from your work is that in 2020 there were 740 000 cancer cases attributable to alcohol. Could you explain in layman's terms how you, researchers, come to these figures? Because the doctors in hospitals don't diagnose the root causes of individual cancer cases, right?

In our global study we wanted to estimate how many cases of cancer could have been avoided if no one in the population consumed alcohol. To do this we used a type of method (population attributable fractions) which uses population-level data. Through this method we combined information on alcohol consumption in countries across the world, the increased risk of developing cancer from drinking alcohol, and estimates of the number of cases of cancer globally in 2020.

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Another question that often comes up is that the risk from alcohol, for instance, from one drink per day for breast cancer, is so small that it's not noteworthy. So why is it still important to raise that awareness?

The risk of breast cancer increases from one alcoholic drink per day. It's important to raise awareness of the link with breast cancer because, while it might seem like a relatively small increase in risk from one drink per day (between 5% and 9% increase per drink per day according to WCRF), breast cancer is a common cancer and a small relative increase in risk can have a large impact overall.

Just within Europe, breast cancer represented over 38,000 cases of cancer caused by alcohol in 2020, making it the cancer type which contributed the most cases caused by alcohol in the region. What's more, breast cancer represented an overwhelming two thirds (66%) of cases of cancer in 2020 caused by alcohol among women in Europe — and of those cases of breast cancer caused by alcohol, a third were due to drinking one or two drinks per day. I think that's noteworthy!
 

What is your personal view of why that awareness is still so low? Despite the evidence we have, campaigns that are run, materials published, but as a recent Danish report showed, only a bit over 20% of the people knew about alcohol and cancer link. Why is that so difficult to understand? Or to believe?

Public awareness of the link between alcohol and cancer is low and this is the case in many countries across the world. I believe that the low public awareness about alcohol and cancer is partly due to the alcohol industry's attempts to block this information from reaching the public by publishing confusing messaging and by interfering with public health policy making. But people should have the right to know about the health risks that come with drinking alcohol and should have the opportunity to make informed decisions about their drinking habits. I believe that action through measures such as adding cancer warning labels on alcohol products could achieve this.

 

It appears that different countries are reviewing their low-risk drinking guidelines recently and the "new" knowledge about alcohol and cancer is the main driver for them to do that. These panels seem to be trying to balance the scientific evidence, which shows that there is no safe level of alcohol consumption when it comes to cancer, with the realistic view of what message would be accepted by the population. What would be your recommendation, what would be the correct low-risk drinking guidelines?

Government drinking guidelines are often based on 'low-risk' drinking, i.e. the level at which the government considers the harms from alcohol are acceptable, and so there's no completely safe level of drinking. The Netherlands has already changed their alcohol guidelines to 'Drink no alcohol or at least not more than one glass per day' and is one of the first countries in Europe to use this messaging. Many alcohol prevention, heart disease, and cancer charities are also adopting messaging around there being 'no safe level of alcohol drinking' and I believe this should be the way forward for governments. I think it is important to encourage the use of clear and consistent messaging that there is no safe limit when it comes to alcohol use.

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You also concluded that alcohol policy has a strong potential to decrease these alcohol-attributable cancer cases. What would be the best interventions?

The most cost-effective policies to reduce alcohol consumption and ultimately the alcohol-related cancer burden are the World Health Organization's three 'Best Buys'. These consist of increasing taxation on alcohol, limiting purchasing availability of alcohol products, and reducing marketing of alcohol to the public. There is also some evidence that adding cancer warnings to alcohol labels, similar to those used on cigarette packets, might discourage people from purchasing alcohol products and increase awareness of the link between alcohol and cancer.

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But we know that effective implementation of these policies relies on enforcement and regulation, which aren't always available in lower-resource settings. So local context is essential for successful alcohol policy and will be key to reducing the burden of cancer caused by alcohol.

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Apart from legislative policy measures, what else? What could be done to increase awareness about that link?

It's not only about increasing awareness of the link between alcohol and cancer (and other diseases and injuries), but also about introducing policy measures to protect underserved groups of people who won't receive that information and be able to make an informed decision about their drinking habits. We also need to provide support to people who want to stop drinking or reduce their alcohol intake which could be through advice from physicians or community groups.

 

If you have followed the EU Beating Cancer Plan process, what do you see are this plan's strengths and weaknesses?

I think Europe's Beating Cancer Plan has some really great action areas spanning from cancer prevention, early detection of cancer, better access to diagnosis and treatment, and improved quality of life for cancer patients and survivors. Specifically, the Beating Cancer Plan has highlighted alcohol use as one of the major risk factors for cancer and a focus of public health action in the EU. I think it's very encouraging that the plan aims to review alcohol taxation and cross-border purchasing in the EU, reduce exposure of young people to alcohol marketing, review promotions on alcoholic drinks, propose a mandatory list of ingredients and health warnings on alcohol labels, and to provide support to member states to implement brief interventions on alcohol in primary health.

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Unfortunately, despite the bold plan, I think a lot of the proposed actions for alcohol are undermined by the use of the wording on reducing 'harmful' alcohol consumption, which gives us the impression that there is a 'harm-free' level of alcohol consumption. We have shown that this is not the case — there is no safe level of alcohol consumption.

What are your own next plans with this topic, and where should the research on alcohol and cancer develop from here? What knowledge is currently missing?

I think more evidence on the relationship between alcohol and the cancer types for which we aren't yet confident about a causal link (e.g. pancreatic cancer, stomach cancer) would benefit alcohol and cancer research. I would also like to see potential improvements in the way we measure alcohol use in epidemiological studies to more accurately predict cancer risk and assess the burden of cancer attributable to alcohol. This might be through things like estimating lifetime alcohol use and patterns of drinking through the life-course and the benefits of quitting drinking alcohol.

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We would also like to find out more about how changes in alcohol policy could reduce alcohol consumption and ultimately alcohol-related cancer burden. We have already estimated the potential number of cancer cases and deaths in the WHO European Region that could be avoided through increases in alcohol taxation, but we would like to determine the potential impact of limiting purchasing availability, restricting marketing of alcohol to the public, or adding cancer warnings on alcohol labels on cancer burden in Europe and other regions.

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Some references:

CRUK UK risk factors study https://www.nature.com/articles/s41416-018-0029-6  

IARC global alcohol study https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(21)00279-5/fulltext

IARC Monographs https://monographs.iarc.who.int/

WCRF expert report https://www.wcrf.org/diet-activity-and-cancer/global-cancer-update-programme/about-the-third-expert-report/

Taxes in WHO European region https://www.sciencedirect.com/science/article/pii/S2666776221002106?via%3Dihub

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The views expressed in this article are those of the authors and do not necessarily represent the decisions, policy, or views of the International Agency for Research on Cancer and World Health Organization.