Can Alcohol Cause Cancer?
I’m aware that drinking alcohol increases the risk of breast cancer, but now I’ve heard that alcohol is responsible for many other types of cancer. How much is too much?
Andrew Weil, M.D. | March 2, 2018
We’ve known for some time that alcohol can increase the risk of several types of cancer. The latest warning on this comes from the American Society of Clinical Oncology (ASCO), an organization comprised of the nation’s leading cancer specialists. In November 2017, the group released a statement that detailed the cancer risk posed by alcohol. It included a discussion of a 2017 ASCO survey of 4,016 Americans, showing that fewer than one in three were aware of the role alcohol plays in cancer and making the point that drinkers face higher risks than nondrinkers for developing cancers of the throat, larynx, esophagus, breast, liver, and colon. The more you drink and the longer you’ve been drinking, the higher your risk, especially of head and neck cancers.
According to ASCO, in 2012 alcohol was responsible for 5.5 percent of all new cases of cancer and 5.8 percent of cancer deaths worldwide. In the U.S., an estimated 3.5 percent of cancer deaths are attributable to drinking. If you flip those numbers, you’ll see that 96.5 percent of those deaths aren’t related to alcohol. And because it’s likely that heavy drinking is associated with most of the deaths, the risk for moderate and light drinking may be negligible.
You may be aware that just one drink a day can increase a woman’s risk of breast cancer. ASCO cited data showing that a daily drink of wine or beer containing about 10 grams of alcohol increases the risk of premenopausal breast cancer by five percent and postmenopausal breast cancer by 9 percent. It’s important to put those numbers in perspective: 5 percent is not very much when you consider the breast cancer risk among 40 year old women is just 1.45 percent over the next 10 years – that comes out to one woman in 69 over 10 years. A five percent increase in that would raise the risk to 1.52 percent. Heavy drinking would raise the risk from 1.45 to 2.33 percent.
Moderate drinking can double the risk of squamous cell carcinoma of the esophagus and mouth and throat cancers compared to the risk of these diseases among nondrinkers. Moderate drinking is also linked to increased risk of breast cancer in women as well as colorectal and laryngeal cancer in men and women. The U.S. Centers for Disease Control and Prevention (CDC) defines moderate drinking as one drink per day for women and two for men; a drink means 12 ounces of beer, five ounces of wine or 1.5 ounces of spirits.
Heavy drinking (eight or more drinks per week for women and 15 or more for men) can put you at five times the risk faced by nondrinkers for mouth and throat cancers and squamous cell esophageal cancer. Heavy drinking also triples the risk of cancer of the larynx, doubles the risk of liver cancer and boosts the risk of breast cancer in women and colorectal cancer in men and women. Bear in mind that doubling the risk means if one in 100 people get a certain type of cancer, twice the risk means that two in 100 will be affected. This is the absolute risk, which helps put percentage increases in perspective.
While the ASCO statement made the point that the greatest risks of cancer are due to heavy and moderate drinking, it noted that even one drink daily or less (such as a single drink a few days a week) was linked to a slightly increased risk for squamous cell cancer of the esophagus, oropharyngeal cancer and breast cancer.
The group also suggested that the number of cancers caused by alcohol might not be complete and that “as evidence continues to accumulate, the list of alcohol-associated cancers is likely to grow.” The statement noted that drinking has been linked to pancreatic and stomach cancer and that alcohol may play a role in lung cancer, but since many habitual drinkers also smoke it’s difficult to show direct correlation.
Bear in mind that drinking alcohol has some positive health effects. Good evidence shows that light to moderate drinking can reduce the risk of heart disease, diabetes and stroke. Heart disease kills more Americans than cancer.
While I don’t think it’s advisable to start drinking as a way to boost health, my feeling is that, if you do drink, an occasional drink is unlikely to do you much harm and may even do you some good. You can read more about the cancer risks alcohol poses in women here.
Andrew Weil, M.D.
Noelle K. LoConte et al, “Alcohol and Cancer: A Statement of the American Society of Clinical Oncology.” Journal of Clinical Oncology, November 7, 2017, DOI: 10.1200/JCO.2017.76.1155