Long-term alcohol use has been linked to higher risks of colorectal cancer, according to a study published Monday in the journal Cancer.
Researchers found that those with heavy lifetime alcohol consumption have up to a 91% higher risk of developing colorectal cancer compared with those who drank very little. That risk significantly increased with consistent heavy consumption, whereas those who quit drinking may have demonstrated decreased risk of precancerous tissue.
“The longer someone drinks, the longer their colon and rectum are exposed damage and impaired repair, both major mechanisms of cancer,” Dr. Lynn M O’Connor, section chief of colon and rectal surgery at Mercy Medical Center and St. Joseph Hospital in New York, told ABC News.
The study followed more than 88,000 adults with no prior history of cancer. Participants reported their alcohol use beginning in early adulthood and were followed for nearly a decade to track cancer outcomes.
Compared with those who averaged one drink or less per week over their lifetime, those who consumed over 14 drinks a week had a 25% higher risk of developing colorectal cancer. The link was even stronger for rectal cancer, where one’s risk nearly doubled.
Rectal cancer is “often more difficult to treat and more involved clinically, which makes screening and early identification all the more important,” Dr. Jeffrey Farma, a colorectal cancer specialist, told ABC News.
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The results come as colorectal cancers are on the rise, especially in younger people.
“We’re seeing an uptick in rectal cancers. If alcohol affects the lower part of the colon differently —we need to understand why,” Dr. Fola May, a GI specialist and associate director of the UCLA Kaiser Permanente Center for Health Equity, told ABC News.
In the study, researchers found the highest risks among people who drank heavily at every stage of life. Those who consistently exceeded recommended drinking limits across each stage of adulthood had a 91% higher risk of colorectal cancer compared with lifelong light drinkers or those with gaps in heavy drinking.
“These numbers are not guarantees, but signals to do something before it’s too late,” May said. “Colorectal cancer is one of the few cancers we can actually prevent or catch early, but fewer than 70% of eligible people get screened.”
The study also looked at adenomas —polyps that can develop into cancer. While heavy drinking was not strongly linked to adenoma risk, those who quit drinking had significantly lower odds of developing nonadvanced adenomas compared to light drinkers.
“These are modifiable risks. The choices people make over time matter, and the body can respond when those risks are reduced,” Farma said.
The results align with a growing body of evidence linking alcohol, a well-recognized carcinogen, to colorectal cancer.
Colorectal screening is recommended for all adults starting at age 45 according to the United States Preventative Services Task Force. Screening tools include annual stool tests, CT scans every five years, or colonoscopies every 10 years.
“Everyone should be screened. It saves lives, and people are dying unnecessarily when they put it off,” May said.
Those who may be at higher risk may need to be screened at an early age or more often than typically recommended.
“If you’ve had prolonged heavy drinking and you develop symptoms like bleeding or persistent changes in bowel habits, you need to be evaluated — even in your 30s,” Farma said. “That’s how we catch this early and save lives.”
Tyler Beauchamp, MD, is a pediatric resident at UNC Children’s Hospital and a member of the ABC News Medical Unit.
