How Does Alcohol Increase Cancer Risk?
With the U.S. surgeon general issuing a recommendation that alcohol should include warning labels for cancer risk, an expert explains the link and what alcohol does to the body.
A new advisory from the U.S. surgeon general on alcohol and cancer risk shares scientific evidence that links drinking alcohol to an increased risk of at least seven different types of cancers, including in the mouth, throat, esophagus, voice box, breast, colon, and rectum.
“When we talk about modifiable risk factors, things we can change in our life [to reduce cancer risk], we always talk about making lifestyle modifications, such as eating healthy, exercising, and making sure we maintain a healthy body weight,” says Dr. Natalie Berger, an oncologist specializing in breast cancer at NewYork-Presbyterian Hudson Valley Hospital. “Reducing or avoiding alcohol is another one of those factors we discuss. There are many factors that contribute to a person’s risk of developing cancer, and we know that alcohol is one of them.”
After tobacco and obesity, alcohol is the third-leading preventable cause of cancer in the United States, contributing to almost 100,000 cancer cases and around 20,000 cancer deaths each year. But less than half of Americans are aware of the relationship between alcohol and cancer risk, according to the advisory, which recommends adding labels on bottles containing alcohol to help warn people of the risk.
Health Matters spoke with Dr. Berger on key takeaways from the advisory, such as how much alcohol increases cancer risk, what occurs in the body after consuming alcohol, and what to keep in mind if you want to cut back.
How much alcohol raises cancer risk?
Dr. Berger: We know that the more a person drinks over time, whether it is beer, wine, or spirits, the higher their risk for cancer. It is important to be mindful of what the defined quantity of one drink means. One standard drink in the U.S means a 5-ounce glass of wine, a 12-ounce beer, or 1.5-ounces of distilled spirits. Patients often ask how much alcohol they can drink, or what is considered too much, but there is no amount we can say with certainty is safe.
Based on studies, the surgeon general’s advisory report looked at absolute risk, which are the chances of developing cancer during a person’s lifetime, based on how much alcohol they consume every day or week.
In a study of 226,162 people, it found that women who drank less than one drink per week, had a cancer risk of about 16.5% in their lifespan. Absolute risk rises to 19% in women who consume one drink daily (seven drinks a week) and to 21.8% with two drinks a day.
Men who drink less than one drink a week have around a 10% chance of alcohol-related cancers in their lifetime. Absolute risk in their lifespan for alcohol-related cancers increases to 11.4% with one drink a day and 13.1% with two drinks a day.
The advisory also examined regular risk for developing cancer related to alcohol in those who drink versus those who do not. For example, an analysis found that there was a 32% increase in breast cancer risk in women who drink more than two drinks a day, compared to those who do not drink at all. This is a substantial amount of cancer cases that can be prevented, the advisory stated, given that there are many people in the U.S. who consume alcohol, and because breast cancer is one of the most common cancers.
How Alcohol Impacts the Body
Over time, ethanol, the type of pure alcohol found in all alcohol-beverages, can cause cancer in at least four different ways, the report noted. Dr. Berger explains how:
- Our livers metabolize alcohol into acetaldehyde.
Acetaldehyde is a compound that binds to and damages DNA, which is the building blocks that make up who we are, and that also tell our cells how and when to divide. When DNA is damaged, it can lead to the development of cancer – cells that were once normal and healthy start to grow out of control and cause a cancerous tumor. - Alcohol induces oxidative stress.
Oxidative stress, which has been associated with the development and progression of cancer, increases inflammation in the body, and can also damage DNA, proteins, and lipids. - Alcohol alters the level of hormones, including estrogen.
There are different ways on how alcohol can affect hormone levels in the body. One is that alcohol can lead to obesity and increased weight gain, and estrogen is made in our fat cells. Obesity is associated with a rise in estrogen levels. Higher estrogen levels can alter breast tissue and damage DNA, increasing the risk of breast cancer, especially hormone receptor-positive breast cancer. Also, it is thought that since estrogen is metabolized in the liver, like a lot of other things. If the liver is busy metabolizing the alcohol, estrogen levels in the blood can increase. - Carcinogens dissolve more easily in alcohol.
When drinking alcohol, it increases the body’s ability to absorb carcinogens, such as from tobacco smoke, which can raise the risk for mouth and throat cancer.
Can damage from alcohol be reversed?
Our hope is that the answer is yes, and research has shown that reducing or eliminating alcohol intake can lower the risk of oral cavity and esophageal cancer. We know that when people quit smoking, it does reduce the risk of cancer down the line. The sooner someone quits, the better. It is the same with alcohol. There could be damage that was done, but the sooner someone cuts back on alcohol, the lower their risk because they are eliminating a toxin from the body, which can reduce their cancer risk. It’s important to remember, it’s never too late to cut back or quit drinking. For heavy drinkers or those who need additional support, it’s important to speak with a healthcare professional for guidance and resources to help with quitting drinking.
What should people keep in mind as they evaluate drinking alcohol and how to cut back or reduce their intake?
While the advisory is important, we do not want to cause fear and panic in people – it is not saying that people cannot drink alcohol, but it is alerting the public of its risks so people can make their own informed decisions. There are many other factors that play into why cancer develops, such as a person’s sex, genetics, family history, diet, and other environmental factors.
For those who want to cut back, I try to emphasize that moderation is key and less is more, especially when it comes to alcohol. If a person tends to drink alcohol every night with dinner, I recommend limiting it to two or three times a week with dinner to start, rather than seven days a week. Cutting back by any amount can be a meaningful gain. The Centers for Disease Control and Prevention offers a tool that can help assess someone’s drinking habits and make a plan to drink less.
Natalie Berger, M.D., is an oncologist and hematologist and an associate director of breast medical oncology at NewYork-Presbyterian Hudson Valley Hospital. Dr. Berger is also an assistant professor of medicine at Columbia University Vagelos College of Physicians and Surgeons’ Division of Hematology and Medical Oncology.