Health Check: does alcohol cause cancer?

Alcohol and cancer is a topic that arouses a lot of controversy: many Australians like the odd drink but don't want to make the connection to cancer, the world's biggest killer.

The World Health Organisation's new World Cancer Report 2014 shows cancer is responsible for 8.2 million deaths in 2012. Around 340,000 of those deaths were the direct result of alcohol consumption.

The link between alcohol and cancer itself is not news. Way back in 1988, the WHO's International Agency for Research on Cancer (IARC) concluded that alcohol consumption was a group one carcinogen - a direct cause of cancer in humans.

What has evolved over the past 26 years is evidence showing alcohol caused more cancers than first thought. Alcohol has now been conclusively shown to cause breast cancer in women, bowel cancer in men, and cancers of the mouth, pharynx, larynx and oesophagus in everyone. There is increasing evidence that alcohol causes liver cancer in both women and men as well.

When it comes to cancer patterns, the IARC is the best of the best - the world's leading cancer scientists, analysing huge population studies within an exhaustive evidentiary framework, to determine beyond doubt the causes of what is now the world's biggest killer.

One of the most interesting aspects of the IARC's work is that, despite the baseless catchphrase "everything gives you cancer", the evidence shows there are only a handful of proven cancer-causing agents:

• tobacco
• the combined effects of obesity, poor diet and physical inactivity
• UV radiation
• alcohol consumption
• viral infections such as hepatitis and human papillomavirus
• asbestos
• salt
• industrial chemicals, many of which have been banned in countries such as Australia.

So in terms of risk, where does alcohol fit into the mix?

The new WHO report shows around 4.2% of all global cancer deaths are directly attributed to alcohol consumption. In Australia, the percentage is likely to be higher (6.5% according to some analyses). The reason for that is simple: the average Australian drinks more than the average individual from most other countries.

The risk equation in terms of alcohol exposure is straightforward: the more you consume, the higher the risk. As with most carcinogens, it's continuous, long-term exposure that does the most damage.

To put some context around the stats, even by the most conservative estimates, more Australians die each year from an alcohol-related cancer than from melanoma.

The good news is that although alcohol is a proven cause of cancer, you can reduce your cancer risk by reducing your alcohol consumption. It's all a matter of informed choice.

Australian guidelines recommend men and women consume no more than two standard alcoholic drinks on any given night to reduce the lifetime risk of alcohol-related harm. If you adhere to the guidelines, you will significantly reduce your cancer risk. But even one or two drinks a day, every day over an extended period, can increase your cancer risk - especially for women.

So, what can regulators do?

Increased awareness would help. We've long made the case for text warnings on alcohol products, just so people can make an informed choice about that extra drink. Warning labels would remind consumers of the risks whenever they're exposed to the product.

Any potentially harmful product should carry a warning for the consumer. A box of matches does. And, while a misused match can cause death, we're not losing more than 2,000 Australians each year to match-related fires and explosions, as we are to alcohol-related cancers.

We've also long made the case that Australia's alcohol taxation system is wrong. Harmful products should be taxed on a proportional basis, linked - where possible - to the agent that causes the harm.

With alcohol products, it's the level of alcohol (and ethanol in the alcohol) that causes cancer, and most the other alcohol-related health problems. The tax component should be linked to the alcohol volume.

That way, as well deterring people from purchasing the most harmful alcohol products, governments have a revenue source to help pay for all the problems alcohol causes and to fund public education programs. (The fact that some wines are cheaper than bottled water says it all.)

Until we get better public policy settings to reduce the impact of cancer-related alcohol, it's up to you to make an informed choice.

This blog also appear on The Conversation