Danielle Shapiro, MD, MPH, Cancer Prevention and Treatment Fund
The link between and alcohol and cancer may surprise you. A 2017 statement by the American Society of Clinical Oncology (ASCO) reports that drinking alcohol increases the risk of cancer of the mouth and throat, vocal cords, esophagus, liver, breast, and colon. The risks are greatest in those with heavy and long-term alcohol use. Even so, moderate drinking can add up over a lifetime, which could be harmful.
What is Moderate Drinking? Heavy Drinking?
According to the National institute of Alcohol Abuse and Alcoholism (NIAAA), “moderate” drinking is 1 drink per day for women and 2 drinks per day for men, but not all “drinks” are equal. A drink is defined as approximately 14g of alcohol, which equals: 1.5 ounces of distilled spirits (e.g., vodka, gin, tequila, etc), 5 ounces of wine, 12 ounces of beer, and 8 ounces of malt liquor.[1,2] (Click here to see the CDC’s fact sheet.)
Heavy drinking is defined as 8 or more drinks per week OR 3 or more drinks per day for women and 15 or more drinks per week OR 4 or more drink per day for men. Most adults who engage in high-risk drinking started as teens. (Click here to see our article on teen drinking.)
Drinking Amount and Cancer Risk
According to the International Agency for Research on Cancer (IARC), a branch of the World Health Organization (WHO), alcohol is a “group 1 carcinogen.” That means it can cause cancer in humans. Group 1 carcinogens include cigarette smoke, UV solar radiation, radon, and asbestos, for example. Alcohol is known to cause six types of cancer, including cancer of the mouth and throat, vocal cords, esophagus (squamous cell), liver, female breast, and colon/rectum. Alcohol may also be tied to cancer of the pancreas, stomach, and lung, but more research is needed to find out for certain. (Click here to see the National Cancer Institute’s Fact Sheet.)
Some of these cancers, such as mouth and throat cancer, are rare (about 1% lifetime risk), while colon cancer and breast cancer are much more common.  Depending on the amount a person drinks, he or she can increase the risk for even rare cancers. For example, moderate drinkers can almost double their lifetime risk of mouth and throat cancer to almost 2%, while heavy drinkers have a 500% increased risk of having mouth or throat cancer, from 1% to 5%.
Scientists believe that when alcohol comes into direct contact with tissue through drinking and swallowing, it causes more damage. For example, in the heaviest drinkers, alcohol raises the lifetime risk of esophagus cancer from about 0.5% to about 2.5%.[1,7]
Women need to be more cautious when drinking any amount of alcohol. The World Cancer Research Fund estimates that for every additional average drink per day, breast cancer risk goes up by 5% pre-menopause and up by 9% after menopause. Alcohol affects the amounts of certain sex hormones circulating in the body. For women who have had hormone receptor-positive breast cancer, 7 or more weekly drinks increased the chances of having a new cancer diagnosed in the other breast from about 5% to about 10%.
How Alcohol Causes Cancer
Scientists believe that alcohol causes cancer in several ways:[1, 4]
- Alcohol (ethanol) is broken down into a toxic substance called acetaldehyde. Acetaldehyde is directly toxic to the body’s cells.
- Alcohol causes damage to cells through a process called free-radical oxidation.
- Alcohol causes the body to absorb less folate (an important B vitamin) and other nutrients (antioxidant vitamins A, C, and E), which naturally repair damage and fight off cancers.
- Alcohol increases the body’s level of estrogen (a sex hormone associated with breast cancer).
Does Quitting Change Your Chances of Developing Cancer or Cancer Recurrence?
Yes, drinking less alcohol on a regular basis reduces cancer risk, even in people who were already diagnosed with cancer. Research has shown that heavy or moderate drinkers who substantially reduce their alcohol consumption will slowly reduce their risk of developing mouth, throat, vocal cord, and esophagus cancer, but it would take 20 years of abstention to reduce the chances of developing those cancers to the lower chances of someone who never drank so frequently. It is not clear whether reducing or giving up drinking after years of moderate or heavy drinking will have much impact for other alcohol-related cancers.
In those who survived an esophagus cancer, drinkers tripled their risk for a new primary cancer diagnosis. On average, the risk of a new cancer diagnosis after esophagus cancer is removed is 8 % to 27%, and continuing heavy drinking will triple that risk.
Among all cancer survivors, heavy drinking caused an 8% increased risk in dying and a 17% increased risk of cancer recurrence. Patients with cancer who abuse alcohol do worse because alcohol causes poorer nutrition, a suppressed immune system, and a weaker heart.
What You Can Do to Lower Cancer Risk for You and Your Family
- . If you drink alcohol, limit drinks to an average of 1 a day for women and 2 a day for men.
- Recognize heavy drinking in a loved one, because the more a person drinks, the greater his or her chances of developing cancer. The “CAGE” questionnaire can help spot heavy drinking. Has the person tried to Cut back? Has the person been Annoyed when asked about drinking? Has the person felt bad or Guilty? Has the person needed a drink first thing in the morning (Eye opener)? Each “yes” counts as 1 point. A score of 2 or more suggests problem drinking.
- Talk with your doctor about your risk. Doctors can refer or offer counseling and treatment services to patients with risky drinking habits.
- Seek help early. Problem drinking can’t be wished away. There are many resources to access information and help. The Substance Abuse and Mental Health Services Administration (SAMHSA), which is part of the U.S. Department of Health and Human Services (HHS) has a toll free hot-line and website. Call 1-800-662-HELP (4357) or visit https://findtreatment.samhsa.gov/ today.
- Practice healthy habits. Eating a diet rich in cancer-fighting nutrients (i.e., fruits and vegetables), exercising, maintaining a healthy weight, reducing stress, and getting restful sleep can all help to lower cancer risk. Don’t smoke, and quit if you do. Drinking and smoking increases cancer risk more than either one alone.
The Bottom Line
To prevent cancer, try to limit your drinking by sticking to a maximum average of 1 a day if you’re a woman and 2 a day if you’re a man.
All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.
- LoConte, NK. et al. Alcohol and Cancer: A Statement of the American Society of Clinical Oncology. Journal of Clinical Oncology. published online before print November 7, 2017. DOI: 10.1200/JCO.2017.76.1155. Available online: http://ascopubs.org/doi/full/10.1200/JCO.2017.76.1155
- Centers for Disease Control and Prevention. Alcohol and Public Health. Fact Sheets- Moderate Drinking. Accessed November 16, 2017. Available online: https://www.cdc.gov/alcohol/fact-sheets/moderate-drinking.htm