A recently released ASCO statement summarizing extensive evidence linking alcohol use to an increased risk of several leading cancers, including breast, colon, and head and neck, called on oncologists “as front-line providers for cancer patients” to help patients reduce excessive alcohol use.1 “Despite the evidence of a strong link between alcohol drinking and certain cancers, ASCO has not previously addressed the topic of alcohol and cancer,” the statement noted, but does so now because its Cancer Prevention Committee “believes a proactive stance by the Society to minimize excessive exposure to alcohol has important implications for cancer prevention.”
The first thing we need to do as oncologists is to assess the amount of alcohol our patients are consuming.— Wendy Y. Chen, MD, MPH
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“This article is very important, because it brings up something we don’t always think about, which is talking to patients about alcohol consumption,” Wendy Y. Chen, MD, MPH, commented in an interview with The ASCO Post. The ASCO statement highlights for oncologists “that this is something we should engage our patients on.” Dr. Chen is Senior Physician, Breast Oncology Center, at Dana-Farber Cancer Institute, and Assistant Professor of Medicine at Harvard Medical School, Boston.
“The first thing we need to do as oncologists is to assess the amount of alcohol our patients are consuming,” Dr. Chen said. “For someone who does drink regularly, talk with them about the increased risk, as the ASCO statement shows, for multiple cancers.”
‘Potentially Modifiable Risk Factor’
“As a potentially modifiable risk factor for cancer, addressing high-risk alcohol use is one strategy to reduce the burden of cancer,” according to the ASCO statement. “In the United States, it has been estimated that 3.5% of all cancer deaths are attributable to drinking alcohol. Alcohol is causally associated with oropharyngeal and laryngeal cancer, esophageal, hepatocellular, breast, and colon cancers. Even modest use of alcohol may increase cancer risk, but the greatest risks are observed with heavy, long-term use.”
As noted in the statement: “The full range of cancers for which alcohol drinking represents a risk factor remains to be clarified. For example, the index of suspicion is high that alcohol drinking leads to excess risk of pancreatic cancer and gastric cancer. For some malignancies, alcohol drinking clearly is statistically associated with increased risk but, because of its strong correlation with other risk factors, it is difficult to discern if alcohol drinking is truly an independent risk factor.”
For example, although alcohol has been consistently and statistically strongly associated with an increased lung cancer risk, cigarette smoking is the overwhelming lung cancer risk factor. “Alcohol and tobacco are probably synergistic,” Dr. Chen said, not only for lung cancer, but for upper digestive and head and neck cancers. It can be difficult to separate out the risks; however, people who smoke cigarettes may be more likely also to drink alcohol.
The idea of alcohol as a modifiable risk factor for cancer is something of which the majority of members of the public were unaware. For example, the ASCO statement on alcohol and cancer was reported by health publications and major media, including ABC and NBC News, Reuters, and The New York Times. Three days after publishing an article about the statement, The New York Times reported in its Evening Briefing: “Among the panic-inducing headlines we published this week, this one stood out: ‘Cancer Doctors Cite Risks of Drinking Alcohol.’” The New York Times reported receiving comments from “nearly 500 readers.”3
“The number of comments in The New York Times clearly says a lot of people did not realize that alcohol is a risk factor for cancer,” Dr. Chen stated. That was also among the findings of the National Cancer Opinion Survey reported by ASCO earlier this year. That survey found nearly 70% of Americans do not recognize alcohol as a risk factor for cancer.4
“As evidence continues to accumulate, the list of alcohol--associated cancers is likely to grow,” according to the ASCO statement.
Excessive vs Moderate Drinking
“Clearly, the greatest cancer risks are concentrated in the heavy and moderate drinker categories. Nevertheless, some cancer risk persists even at low levels of consumption,” the ASCO statement reported. “On the basis of the lesser overall cancer risk at the lower end of the dose-response continuum,” the statement continued, the World Cancer Research Fund/American Institute for Cancer Research made the following recommendation: ‘If alcoholic drinks are consumed, limit consumption to two drinks a day for men and one drink a day for women.’ They also recommend that, ‘for cancer prevention, it’s best not to drink alcohol.’”
Dr. Chen added that “regular drinking” averages those daily drinks over a week or more. That means someone who has two drinks every other day would be considered a regular user because that averages out to one drink per day vs someone who has one drink once a week. Heavy drinking was defined in the ASCO statement as “8 or more drinks per week or 3 or more drinks per day for women and as 15 or more drinks per week or 4 or more drinks per day for men.”
Clifford A. Hudis, MD, FACP, FASCO
The number of servings of alcohol is important because of the dose-response relationship. “The more that a person drinks, and the longer the period of time, the greater the risk of development of cancer, especially head and neck cancers,” according to the ASCO statement. “It’s a pretty linear dose-response,” ASCO CEO Clifford A. Hudis, MD, FACP, FASCO, was quoted as saying in an article in The New York Times.2
Reporting Drinking Behaviors
“Defining risk-drinking can be challenging, because the amount of ethanol contained in an alcoholic beverage will vary considerably depending on the type of alcohol (eg, beer, wine, or spirits) and the size of the drink consumed,” according to the ASCO statement. The National Institute of Alcohol Abuse and Alcoholism defines a standard drink as one that contains roughly 14 g of pure alcohol (the equivalent of 1.5 ounces of distilled spirits), 5 ounces of wine, or 12 ounces of regular beer. “However, evidence shows drinkers are often unaware of how standard drinks are defined and these standard drink sizes are commonly exceeded,” the ASCO statement noted.
Dr. Chen, who is also an epidemiologist, acknowledged that it can be difficult to know precise drink sizes being served but reported that epidemiologic studies looking at drinking patterns have found that “besides binging around the Super Bowl or other events, people’s alcohol use is actually relatively constant throughout the year. If you look at their average consumption, it actually is something that is remarkably steady. If you ask people how many drinks on average do you have, unless they are alcoholic individuals, they can report that quite reliably.”
She explained that in referring to alcoholic individuals, she meant those whose ability to do daily activities is compromised by alcohol and who have not been able to stop drinking. Those who are dysfunctional drinkers or alcoholic individuals, she said, tend not to accurately estimate their alcohol consumption.
Cardiovascular Health and Alcohol Consumption
Discussing drinking with patients should become part of routine clinical care, Dr. Chen said, such as talking about tobacco use and helping patients who smoke to quit. “With alcohol, it is trickier, because there is quite a lot of data that suggest a potential benefit in terms of decreasing cardiovascular risk. Many people are cured of their cancer, and we need to think about their risks of other diseases.”
The ASCO statement refers to “conflicting data about the heart health of alcohol, especially red wine,” as a “barrier to addressing alcohol and cancer risk in the oncology setting. The benefit of alcohol consumption on cardiovascular health likely has been overstated.” As reviewed elsewhere in the statement, “the risk of cancer is increased even with low levels of alcohol consumption, so the net effect of alcohol is harmful. Thus, alcohol consumption should not be recommended to prevent cardiovascular disease or all-cause mortality.”
However, there is a significant amount of epidemiologic literature that has looked at the beneficial effects of alcohol consumption and cardiovascular disease. “One of the ways used to tell whether someone drinks alcohol is to look at their high-density lipoprotein,” Dr. Chen stated. “In someone who drinks alcohol regularly, their good cholesterol is always higher. So, we do know that alcohol has a beneficial effect on a lipid profile. It is biologically plausible that something that has a beneficial effect on the lipid profile could then have a beneficial effect on cardiovascular disease,” Dr. Chen noted. Additionally, alcohol, especially wine, “may also have other antioxidants and other benefits in terms of vasodiliation, “but there are no randomized trial data.”
People who average a serving of alcohol a day “in general are healthier, at least in the United States,” Dr. Chen said. Looking at alcohol and health produces a U-shaped curve, Dr. Chen noted. “People who drink just that moderate amount, or a serving a day or several servings a week, are generally the healthiest in the United States.” In other countries, particularly those where alcohol is less prevalent, “these relationships don’t necessarily hold,” Dr. Chen added.
‘More Nuanced Discussion of Risk’
The New York Times Evening Briefing also referred to a column, The Upshot,5 which advocated “a more nuanced discussion of risk”. The author reported “a 40-year-old woman has an absolute risk of 1.45% of developing breast cancer in the next 10 years.” Moderate drinking would increase the risk of breast cancer by 23% (a relative risk of 1.23 compared with a nondrinker), but she would still only have an absolute risk of 1.78%. For heavy drinkers, the absolute risk would be 2.33%.
It is biologically plausible that something that has a beneficial effect on the lipid profile could then have a beneficial effect on cardiovascular disease, but there are no randomized trial data.— Wendy Y. Chen, MD, MPH
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Dr. Chen agreed that the data on alcohol and cancer deserve a nuanced discussion with patients. “At the lower levels of use” (several servings per week, averaging less than one serving per day), “it is not even clear there is an increase at all,” she said.
Dr. Chen said, “As oncologists, we do need to be careful about saying, ‘Don’t do that. Do this.’ We also need to be careful about not overpromising. Not everyone who drinks is going to get breast cancer and not everyone who doesn’t drink is never going to get breast cancer. That is the tricky thing about risk factors.”
Impact on Cancer Treatment
Little is known about how alcohol use impacts the treatment of cancer, and research on this is in the beginning stages. Dr. Chen pointed out that chemotherapy and other agents are metabolized through the liver. “If you are drinking two to three drinks a day, you are putting extra stress on your liver.”
“Among my patients who are regular alcohol drinkers (usually one or two servings a day), I recommend that at least while they are on treatment, they drink less than that, just because you can overtax the liver. I don’t tell them they need to abstain completely, but I do tell them you need to keep it down to several servings per week.”
DISCLOSURE: Dr. Chen reported no conflicts of interest.
REFERENCES
1. LoConte NK, Brewster AM, Kaur JS, et al: Alcohol and cancer: A statement of the American Society of Clinical Oncology. J Clin Oncol. November 7, 2017 (early release online).
2. Rabin RC: Cancer doctors cite risks of drinking alcohol. The New York Times, November 7, 2017.
3. Zraick K, Stevenson S: Roy Moore, Lebanon, Louis C.K.: Your Friday evening briefing. The New York Times, November 10, 2017.
5. Carroll AE: A link between alcohol and cancer? It’s not nearly as scary as it seems. The New York Times, November 10, 2017.
