Alcohol a direct cause of seven forms of cancer, study finds

There is strong evidence that alcohol causes seven types of cancer and probably others, according to the findings of a new study.

The study sparked renewed calls for regular drinkers to be encouraged to take alcohol-free days and for alcohol packaging to carry warning labels.

The analysis of existing research, published in the scientific journal Addiction, concludes that there is more than simply a link or statistical association between alcohol and cancer that could be explained by something else.

There is now enough credible evidence to say conclusively that drinking is a direct cause of the disease, according to Jennie Connor, of the preventive and social medicine department at Otago University in New Zealand.

Alcohol is estimated to have caused about half a million deaths from cancer in 2012 alone – 5.8 per cent of cancer deaths worldwide, she said.

The highest risks are from heavy drinking, but even people who drink at low levels are at risk.

Connor’s review of existing research linked alcohol to cancer of the mouth and throat, larynx, oesophagus, liver, colon, bowel and breast.

“Confirmation of specific biological mechanisms by which alcohol increases the incidence of each type of cancer is not required to infer that alcohol is a cause.”

She said that based on current evidence, there is no safe level of drinking with respect to cancer though the risks are reduced for some cancers when people stop drinking.

The supposed health benefits of drinking were “seen increasingly as disingenuous or irrelevant in comparison to the increase in risk of a range of cancers”.

Growing evidence suggested that alcohol was also likely to cause skin, prostate and pancreatic cancer, she added. Emphasising that a drinker’s risk increased in relation to the amount consumed, Connor said: “For all these there is a dose-response relationship.”

Scientists are still researching how alcohol can lead to cancer. One theory is that alcohol damages DNA.

Susannah Brown, science programme manager for the World Cancer Research Fund (WCRF), said of the new work: "Many people believe that alcohol consumption is only linked to liver cancer, but this review confirms the findings of our Continuous Update Project that alcohol is strongly linked to an increased risk of a number of different cancers, including two of the most common — bowel and breast cancer.

“Among other evidence, we see the risk increasing as the amount of alcohol consumed increases, and we agree that there is solid evidence to conclude that alcohol consumption directly causes cancer.

“For cancer prevention, we have long recommended that people should not drink alcohol at all, but we understand that this can be easier said than done.”

The WCRF has previously said that drinking three alcoholic drinks or more per day increases the risk of stomach cancer

It also found strong evidence for a link with other cancers, including mouth and throat, liver, bowel and breast.

Additional reporting: PA