No Confusion: Alcohol Causes Seven Cancers

There is "strong evidence" that alcohol causes seven cancers, and other evidence indicates that it "probably" causes more, according to a new literature review published online July 21 inAddiction.

Epidemiologic evidence supports a causal association of alcohol consumption and cancers of the oropharynx, larynx, esophagus, liver, colon, rectum, and female breast, says Jennie Connor, MB, ChB, MPH, from the Department of Preventive and Social Medicine, University of Otago, in Dunegin, New Zealand.

In short, alcohol causes cancer.

This is not news, says Dr Connor. The International Agency for Research on Cancer (IARC) and other agencies have long identified alcohol consumption as being causally associated with these seven cancers.

So why did Dr Connor, who is an epidemiologist and physician, write a new review? Because she wants to "clarify the strength of the evidence" in an "accessible way."

There is "confusion" about the statement, "Alcohol causes cancer," explains Dr Connor.

Public and scientific discussion about alcohol and cancer has muted the truth about causality, she suggests.

"In the public and the media, statements made by the world's experts are often given the same weight as messages from alcohol companies and their scientists. Overall messages become unclear. For these reasons, the journal [Addiction] has tagged this piece [her review] as 'For Debate,' " she told Medscape Medical News.

The use of causal language in scientific and public discussions is "patchy," she writes.

For example, articles and newspaper stories often use expressions such as "alcohol-related cancer" and "alcohol-attributable cancer"; they refer to a "link" between alcohol and cancer and to the effect of alcohol on "the risk of cancer."

These wordings "incorporate an implicit causal association, but are easily interpreted as something less than cancer being caused by drinking," observes Dr Connor.

"Stop drinking alcohol" is a catch phrase that could be ― but is not ― akin to "stop smoking," she also suggests.

"Currently, alcohol's causal role is perceived to be more complex than tobacco's, and the solution suggested by the smoking analogy — that we should all reduce and eventually give up drinking alcohol — is widely unacceptable," writes Dr Connor.

The newly published review "reinforces the need for the public to be made aware of the causal link between alcohol and cancer," said Colin Shevills, from the Alcohol Health Alliance UK, in a press statement.

"Research shows that only around 1 in 10 people [in the UK] are currently aware of the alcohol-cancer link," he said.

"People have the right to know about the impact of alcohol on their health, including its link with cancer, so that they can make informed choices about how much they drink," added Shevills.

The lack of clarity about alcohol causing cancer, Dr Connor believes, is related to alcohol industry propaganda as well as the fact that the "epidemiological basis for causal inference is an iterative process that is never completed fully."