ALCOHOL DRINKING LINKED TO CANCER

For the first time, the American Society of Clinical Oncology (ASCO) has formally stated that alcohol drinking is a risk factor for multiple malignancies and is potentially modifiable.

Furthermore, the organization believes their new "proactive stance" to minimize excessive alcohol intake has "important implications for cancer prevention."

"Even modest use of alcohol may increase cancer risk, but the greatest risks are observed with heavy, long-term use," write the ASCO statement authors, led by Noelle LoConte, MD, from the University of Wisconsin-Madison.

"Therefore, limiting alcohol intake is a means to prevent cancer," Dr LoConte said in a statement. "The good news is that, just like people wear sunscreen to limit their risk of skin cancer, limiting alcohol intake is one more thing people can do to reduce their overall risk of developing cancer."

ASCO's statement, published online November 6 in the Journal of Clinical Oncology, has received widespread coverage in mainstream media.

"The message is not, 'Don't drink.' It's 'If you want to reduce your cancer risk, drink less. And if you don't drink, don't start,'" Dr LoConte told The New York Times. "It's different than tobacco, where we say, 'Never smoke. Don't start.' This is a little more subtle."

ASCO encourages oncologists to join their efforts: "Oncology providers can serve as community advisors and leaders and can help raise the awareness of alcohol as a cancer risk behavior."

However, the organization also says there is "low physician knowledge of alcohol use and cancer risk."

The general public also has low awareness. In a recent poll conducted by ASCO, 70% of Americans did not recognize drinking alcohol as a cancer risk factor, as reportedby Medscape Medical News.

"People typically don't associate drinking beer, wine, and hard liquor with increasing their risk of developing cancer in their lifetimes," said ASCO President Bruce Johnson, MD. "However, the link between increased alcohol consumption and cancer has been firmly established."

In its statement, ASCO notes that alcohol consumption is causally associated with oropharyngeal and laryngeal cancer, esophageal cancer, hepatocellular carcinoma, breast cancer, and colon cancer. However, alcohol may be a risk factor for other malignancies, including pancreatic and gastric cancers.

In total, ASCO estimates that 5% to 6% of new cancers and cancer deaths globally are directly attributable to alcohol.

A variety of causative mechanisms may be at play, depending on the particular cancer. Perhaps best known is the effect of alcohol on circulating estrogens, a pathway with relevance to breast cancer.

The American Heart Association, American Cancer Society, and US Department of Health and Human Services currently recommend that men limit intake to one to two drinks per day and women to one drink per dayHowever, the ASCO statement authors observe that a meta-analysis found that one drink per day or less was still associated with some elevated risk for squamous cell carcinoma of the esophagus, oropharyngeal cancer, and breast cancer (Ann Oncol.2013;24:301-308).

Defining risk-drinking can be "challenging," say the statement authors, because the amount of ethanol in a drink varies depending on the type of alcohol (eg, beer, wine, or spirits) and its size.

Conflicting data about the impact of alcohol, especially red wine, on the heart is an "additional barrier" to addressing its related cancer risk. But recent research (Addiction. 2017;112:230-232) has cast doubt on those positive health claims studies, revealing multiple confounders, including frequent classification of former and occasional alcohol drinkers as nondrinkers, say the statement authors.

ASCO says that it joins a "growing number" of cancer care and public health organizations that support strategies designed to prevent high-risk alcohol consumption. Its statement offers evidence-based policy recommendations to reduce excessive alcohol consumption, as follows: 

Two of the five statement authors have financial ties to a pharmaceutical company.

J Clin Oncol. Published online November 7, 2017. Full text