Your happy hour habits could raise your cancer risk

Doctors say many people are surprised to learn alcohol raises the risk of certain cancers, such as liver, colorectal and breast cancer. And cancer patients say they aren’t always aware of the increased risk until after they have been diagnosed.

As awareness increases—the former U.S. surgeon general recently called for adding warning labels on alcoholic beverages—more people are rethinking their drinking habits. On social-media sites like Reddit, cancer patients talk about replacing alcohol with cannabis, although this, too, has health issues. Others opt for mocktails or nothing at all.

“I drank my whole 20s. I was at events and happy hours every night," says Lauren Nostro, a 35-year-old creative strategist who lives in Buffalo, N.Y., and used to work in the music industry.

After being diagnosed with an aggressive form of breast cancer at the age of 30, she knew she needed to make some changes. Three years ago, she stopped drinking. Before she was diagnosed with breast cancer she says she was unaware that alcohol was a risk factor.

“When you actually learn about the negative effects of alcohol, especially as it relates to women and cancer, there’s no justification for me to want to do it," she says. “It’s like, why even?"

Alcohol directly contributes to roughly 100,000 cancer cases a year in the U.S., and 20,000 annual deaths. It increases the risk of seven cancers. For some—like liver, head and neck, and colorectal cancer—the increased risk comes with moderate to heavy drinking. For others—like breast and esophageal cancer—it increases even with light drinking.

Decision factors

Jennifer Hay, an attending psychologist and behavioral scientist at Memorial Sloan Kettering Cancer Center, studies how people make decisions about cancer risk.

About 70% of people in the U.S. don’t know that alcohol is a cancer risk factor, according to a 2021 study Hay co-wrote in the journal Preventive Medicine Reports.

“Awareness is really frustratingly low," says Hay. “We really need to make all of those changes in alcohol that we did with tobacco."

The question about cancer recurrence is still being studied, Hay says. There are likely some cancers where people can reduce their risk of recurrence by drinking less and others where it doesn’t matter as much. “But there’s lots of reasons to drink less for cancer survivors," she notes.

A 2023 study in the journal Cancer found that in women who have already had breast cancer, drinking alcohol wasn’t associated with an increased risk of having a recurrence.

It’s possible that the women who drank alcohol had healthier diets or exercise—which are known to reduce the risk of breast cancer—but Marilyn Kwan, lead author of the study and a senior research scientist with Kaiser Permanente Northern California, says they controlled for these and other relevant factors.

Kwan says other studies have produced mixed results. So there is no conclusive evidence to make recommendations on drinking alcohol to prevent recurrence of breast cancer.

Cutting down

Still, breast cancer oncologists say they generally emphasize minimizing alcohol consumption to reduce the risk of recurrence.

Dr. Larry Norton, a breast cancer oncologist and medical director of breast cancer at Memorial Sloan Kettering, says the data on cancer and alcohol is messy. Because the studies are observational, based on what people report, they can be misleading.

Many people don’t recall accurately or tend to minimize how much they say they drink. Plus, the people who say they don’t drink any alcohol may have previously been excessive drinkers.

Also, people who report drinking alcohol may have other risk factors that would increase their cancer risk.

Norton says he’s been giving his patients the same advice for years. There is no need to completely abstain from drinking alcohol; to minimize your risk, limit alcoholic drinks to occasional social interactions and to two to three drinks a week.

Similarly Dr. Cindy Cen, a breast surgeon at Northwell Health Cancer Institute in New Hyde Park, N.Y., advises her patients to limit alcohol to two drinks a week.

Some patients are fine with the advice. Others struggle a little bit more.

“But hopefully having the conversation makes them have a second thought," she says. Even pouring a smaller glass of wine can help.

“I really think this is one of the few things that women can do to modify their breast cancer risk," Cen says. “We don’t know so much about what causes breast cancer. Alcohol intake is something you have control over."

Weekly limits

Dr. Anne Peled is a breast surgeon at Sutter Health California Pacific Medical Center in San Francisco and a breast cancer survivor. The 44-year-old Mill Valley, Calif., resident was diagnosed with breast cancer when she was 37.

“I think that highlighting that there are varying degrees of impact based on how much you’re drinking, especially for breast cancer, is really important," says Peled.

She recommends limiting alcoholic beverages to a maximum of three to five a week. She stresses to her patients not to feel guilty about occasionally drinking. “I don’t want people to feel bad if they want to have a glass of champagne to celebrate with friends."

It’s when people are having one or more alcoholic drinks a day that she tells them to dial back. The absolute risk of developing breast cancer over a woman’s lifespan is 11.3%—or 11 out of 100 women—for those who drink less than one drink a week compared with 13% for those who have one drink a day. It jumps to 15.3% for those who have two drinks a day.

Peled says she drinks less than before having breast cancer. She didn’t used to keep track of how much she drank. Now, she is conscious of it. “If I have a night where I have two drinks out, I think about it the following weekend in a way I just didn’t do before I had breast cancer," she says.

Write to Sumathi Reddy at Sumathi.Reddy@wsj.com