Sobering Figures: Alcohol's Link to GI Cancer

Medscape

06-06-2025

This transcript has been edited for clarity.
In January 2025, the US Surgeon General released an important advisory that 'highlights alcohol use as a leading preventable cause of cancer in the United States, contributing to nearly 100,000 cancer cases and about 20,000 cancer deaths each year.' This is in line with epidemiologic evidence for the carcinogenicity of alcohol.
However, the advisory also noted that approximately 72% of American adults drink alcohol at least once a week, and fewer than half realize that alcohol use contributes to an increase in cancer risk.
In this video, we will explore the research linking alcohol to gastrointestinal (GI) cancers and suggest ways that physicians and public health experts can help individuals dramatically reduce their alcohol consumption. Through careful discussions in the clinic and public health initiatives, we can hopefully prevent many cancer deaths related to alcohol use.
The Toll of Alcohol-Associated GI Cancer
The association between alcohol consumption and cancer risk was first appreciated during the late 1980s. Over time, a growing body of research has demonstrated 'a causal relationship between alcohol use and increased risk for at least seven different types of cancer, including breast (in women), colorectum, esophagus, liver, mouth (oral cavity), throat (pharynx), and voice box (larynx).'
The advisory publication noted that in 2020, approximately 741,300 patients developed cancer in part due to alcohol. In the United States, there are approximately 20,000 cancer deaths annually related to alcohol consumption, more than the number of alcohol-related motor vehicle collisions each year, which totals 13,500.
Breast cancer makes up 60% of cancer-related deaths for women, while liver cancer (approximately 33%) and colorectal cancer (approximately 21%) make up the most cancer-related deaths for men. These figures should be sobering.
Although the risk of developing cancer in people who consume fewer than two drinks per day is lower compared with higher levels of alcohol ingestion, there are a greater number of people who consume one to two drinks per day. Therefore, the total number of cancer cases is similar. In 2020, 185,100 patients who drank one to two drinks daily developed cancer attributed to alcohol usage, compared with 153,400 patients who consumed four to six drinks per day and 192,900 patients who consumed more than six drinks per day.
A standard drink of alcohol amounts to 5 fluid ounces of wine, 12 fluid ounces of beer, or 1.5 fluid ounces of hard liquor.
Knowledge Gap
The International Agency for Research on Cancer — a specialty arm of the World Health Organization — now classifies alcohol as a Group 1 carcinogen along with tobacco, asbestos, and formaldehyde. In fact, 25 years ago, the US National Toxicology Program announced that alcoholic beverage consumption is carcinogenic.
Yet, there remains a knowledge gap among the American public about the fact that alcohol is a strong cancer risk factor. A 2019 survey indicated that only 45% of Americans realized alcohol is a cancer risk factor, while those surveyed had higher awareness of the cancer risks posed by other factors, such as radiation exposure (91%), tobacco (89%), and asbestos (81%).
Scientists have been studying alcohol as a potential risk factor for cancer over 20 years, using the same template of observational studies that researchers previously applied to studying smoking as a cancer risk factor.
A large global meta-analysis comprising 572 research studies and 486,538 cancer deaths concluded that alcohol is indeed a cancer risk factor. A pooled analysis of 26 studies found the odds of developing oral cancer increased by 40% for those who drank one alcoholic beverage daily compared with those who did not. Furthermore, another meta-analysis showed the relative risk of cancer development compared with people who don't drink was 1.0 for light drinkers, 1.21 for moderate drinkers, and 1.52 for heavy drinkers (ie, more than four drinks per day).
How Alcohol Causes Cancer
Acetaldehyde is a breakdown byproduct of alcohol that can cause cancer by binding to DNA and damaging it. As a result, a cell can begin to grow uncontrollably and produce a cancerous tumor. In addition, alcohol can produce reactive oxygen species, which has the potential to create inflammation through oxidation, also damaging DNA, proteins, and lipids.
Studies have shown that providing ethanol or acetaldehyde, which is the metabolic breakdown product of ethanol, led rats to develop more tumors in the body compared with controls. Alcohol can even increase estrogen levels, which can potentially predispose to breast cancer development.
Smoking while drinking poses additional risks. Carcinogens from tobacco smoke can dissolve in alcohol liquid and more easily enter the body, which is especially concerning for the potential contribution to throat and oral cancers. Acetaldehyde can sometimes be used as a food additive and aroma agent, and is a significant carcinogenic component found in cigarette smoke. The acetaldehyde concentration in cigarette smoke is 1000 times greater than that in other significant carcinogens such as polycyclic aromatic hydrocarbons or nitrosamines from tobacco. Drinking alcohol in combination with smoking cigarettes can have a synergistic negative effect on the risk for colorectal cancer, and the combination can have a sevenfold effect on the upper digestive tract's exposure to carcinogenic acetaldehyde.
Additional research has focused on whether folate deficiency, sometimes caused by heavy alcohol use, might also place patients at risk through an alternative pathway.
Esophageal and Liver Cancer
According to the National Cancer Institute (NCI), heavy alcohol consumption can increase esophageal cancer risk fivefold. Even light drinking can increase the risk by 1.3-fold, highlighting the importance of limiting alcohol consumption.
The NCI also reports that heavy alcohol ingestion can multiply the risk of developing hepatocellular carcinoma and intrahepatic cholangiocarcinoma by two times compared with the regular population.
Although additional research needs to be conducted, it has been hypothesized that alcohol can cause liver cancer by altering the immune response, causing reactive oxygen species production, and producing changes in the immune response.
Unfortunately, alcohol can act synergistically with hepatitis B and C to cause liver cancer.
Also, consistently drinking two or more alcoholic beverages per day is associated with an increased risk for liver cancer.
Gastric Cancer
Recent studies have shown that alcohol consumption could increase gastric cancer risk. Acetaldehydes may act as a possible mechanism by creating a local toxic effect, and ethanol may also disturb gastric mucosal protection.
A meta-analysis that reviewed 10 case-control studies investigating alcohol and gastric cancer risks validated it as a risk factor even at low levels of alcohol consumption. A Korean population-based retrospective cohort study found that 'the risk of GI cancer increased linearly with the frequency of drinking in a dose-dependent manner.'
Pancreatic Cancer
The same Korean study found that the risk for pancreatic cancer increased with weekly alcohol drinking.
A meta-analysis published in the British Journal of Cancer also showed a 20% increase in pancreatic cancer risk with alcohol consumption.
In a study of over 450,000 Americans living in California, Florida, Louisiana, North Carolina, Pennsylvania, and New Jersey, the risk of developing pancreatic cancer in heavy alcohol users (at least three drinks per day) was 1.35 compared with light users (less than one drink per day) in never smokers.
Another study, of over 33,000 patients in Sweden, found the relative risk of pancreatic cancer for intermediate and heavy alcohol use was 2.13 in former smokers.
Colorectal Cancer
In 2025, the NCI published a guide indicating that moderate to heavy alcohol consumption is associated with a 1.2- to 1.5-fold increased risk for colorectal cancer compared with patients who were abstinent.
In an earlier review, from 2015, researchers showed that alcohol consumption of more than 30 grams per day was associated with an increased risk of developing colorectal cancer. Estimates from the World Cancer Research Fund/American Institute for Cancer Research indicate that there was a 9% risk of developing colorectal cancer for every 10 grams of alcohol consumed daily.
In addition, folate deficiency has been shown to worsen the effects of drinking alcohol on colorectal cancer risks.
A 2022 meta-analysis published in Clinical Gastroenterology and Hepatology found that consuming alcohol was associated with a 1.71 relative risk of developing early-onset colorectal cancer. Interestingly, cigarette smoking was not statistically significant for establishing such an association. Consumption of processed meat and fried foods, as well as lack of exercise, also contributed to the development of early-onset colorectal cancer. As physicians, we should encourage patients to make lifestyle modifications to avoid those other risk factors.
While additional research needs to be conducted, a cohort study in California and Hawaii, led by Dr Song-Yi Park, indicated that the relationship between alcohol and colorectal cancer might vary by ethnicity. In addition, it found that colorectal cancer risk was increased by wine and beer, but not liquor. The association with alcohol was greatest for rectal and left colon cancers.
Public Health Approaches
Alcohol is the most consumed drug in the United States, a statistic that requires validated approaches for addressing.
In the future, Congress can vote to include alcohol warning labels on bottles and cans. There's evidence that health warning labels are effective in teaching the public about alcohol-induced health consequences. Interestingly, multiple studies have illustrated a decrease in alcohol consumption following viewership of alcohol warning labels. In addition, alcohol warning labels depicting liver cancer or negative alcohol consequences have been shown to reduce drinking and drunk driver situations.
A 2024 meta-analysis showed with 'moderate certainty' that alcohol warning labels might decrease selection of alcoholic drinks and drinking before driving. However, there was 'low evidence' demonstrating that warning labels might reduce alcohol drinking per occasion, or alcohol drinking speeds, which would be important considerations at parties and social gatherings.
A 2020 study showed that alcohol selection was lower for all kinds of alcohol warning labels compared with no warning labels. Specifically, alcoholic drink selection was 56% with warning labels that consisted of an image and text, 49% for image only, and 61% for text only.
During the 1990s and 2000s, physicians and public health experts learned a lot about how to motivate patients to quit smoking. One successful public health approach was the use of the transtheoretical model, where patients go through various stages, such as precontemplation, contemplation, preparation, action, and maintenance, when trying to decide when to quit smoking. This behavioral modification model could be used for alcohol prevention too.
Key public policy interventions also helped, including a tobacco taxation, advertising bans, and tobacco marketing restrictions in smoke-free zones. Similar interventions could work well for alcohol. Alcohol taxation can be used to deter heavy drinkers and young drinkers who don't have as much money to spend, given that tobacco taxation was successful for smoking reductions.
Furthermore, policies could be set to maintain minimum unit pricing to prevent the sale of ultracheap liquor. States could also limit the hours of alcohol purchasing or even the days, such as banning alcohol sales on Sunday. These public health strategies could work in tandem to help decrease alcohol drinking rates in the United States.
Alcohol and smoking are very similar social activities that for years were depicted as stylish and cool in movies and on TV. Then smoking ads were banned on TV through the Public Health Cigarette Smoking Act of 1970. During the 1970s, cigarette companies shifted their advertising from TV to print.
So, it would be important in the future to ban alcohol ads from all media and printed marketing.
As highlighted by the World Health Organization, advertising bans and restrictions were helpful in Nordic countries with decreasing the per-capita drinking amount.
Finally, physicians should screen patients for heavy alcohol consumption using the validated AUDIT- C questionnaire and biomarkers such as phosphatidyl ethanol. When needed, Alcoholics Anonymous or a similar 12-step program can be offered to patients who drink heavily to reduce alcohol consumption.
Tips to Reduce Alcohol Consumption
Here are some helpful tips to encourage patients and friends to reduce alcohol consumption.
Set a quit date and avoid triggers such as meeting friends at bars.
Drink mocktails at social gatherings and parties. Patients can also choose from a plethora of innovative and tasty alcohol-free beers when drinking with friends. Several beer companies, such as Heineken, Budweiser, Guinness, and Samuel Adams, have developed great alcohol-free beer alternatives, which are extremely helpful for patients trying to remain abstinent and also for those trying to prevent cancer.
Mass media initiatives such as the Ad Council and celebrity public service announcement television spots could be used to shift social norms around alcohol consumption. Public service announcements could also be shared at sporting events and concerts where alcohol consumption is common.
Public health campaigns could place posters in bars and liquor stores informing consumers about the link between alcohol and cancer.
Social media could teach target populations about alcohol reduction in fun and engaging ways.
By talking with patients in clinic and working on public health campaigns, gastroenterologists have a unique opportunity to inspire behavioral lifestyle changes in patients and to prevent many cancers.