The Sobering Truth: How Alcohol Affects Cancer Risk

From Dry January to the rise of nonalcoholic drink alternatives, lots of people are rethinking their relationship with alcohol. And that’s a good thing, given all the harmful effects it can have on physical and mental health — including an increased risk of cancer.

The International Agency for Research on Cancer (IARC) reports that alcohol is a known carcinogen, meaning it’s proven to cause cancer. In fact, one study estimates that about 20,000 cancer-related deaths each year are due to alcohol consumption.

Cancer specialist Suneel Kamath, MD, discusses the link between alcohol and cancer.

How does alcohol increase cancer risk?

Though researchers aren’t yet exactly sure how alcohol causes cancer, it’s known to have negative effects on the entire body. It increases the production of free radicals, unstable molecules that can wreak havoc on your body.

In particular, your liver metabolizes alcohol into a toxic chemical called acetaldehyde, a known carcinogen that contributes to free radicals. Acetaldehyde can damage DNA and interfere with your cells’ ability to fix that damage. And when DNA can’t be repaired properly, abnormal cells grow — aka cancer.

“Too many free radicals lead to oxidative stress, which leads to DNA damage in cells and can contribute to diseases like cancer,” Dr. Kamath explains. “Your body can repair some of the damage, but constant exposure can overwhelm those cleanup operations.”

What types of cancer can alcohol cause?

Because the toxic effects of acetaldehyde can affect your entire body, drinking raises your risk of various types of cancer. Here’s a look at each type and how alcohol can contribute:

• Liver cancer: Long-term heavy alcohol use is associated with liver inflammation and cirrhosis, the main risk factor for the most common type of liver cancer.
• Some head and neck cancers: Alcohol directly exposes the delicate tissues of your mouth and throat to damage, increasing the risk of cancers in these areas, especially if you also smoke.
• Breast cancer: Acetaldehyde has been shown to raise levels of certain hormones like estrogen, which has been linked to higher breast cancer risk, especially in women.
• Stomach and esophagus cancer: Alcohol can irritate and damage the lining of the stomach and esophagus over time. One review found that people who drank alcohol had about a 39% higher risk of developing gastric cancer than those who didn’t. Smoking makes things even worse.
• Colorectal cancer: As alcohol moves through your digestive system, it can irritate and damage the lining of your colon and rectum. Over time, that stress raises the risk of colorectal cancer, especially with regular or heavy drinking.

Alcohol may also increase the risk of prostate cancer, pancreatic cancer and cervical cancer.

For cancer survivors, there’s some evidence that continued alcohol use may increase the risk of cancer coming back (recurrence). It can also increase the chances of developing a new cancer. Yet a large study found that nearly 80% of cancer survivors continue to drink alcohol.

“Thanks to earlier diagnoses and better treatments, more and more people are surviving cancer,” shares Dr. Kamath. “I encourage people to live as healthily as possible after cancer treatment. That includes limiting alcohol intake as much as possible."

How to reduce your risk

When it comes to how much alcohol you should drink, less is better. The Dietary Guidelines for Americans recommend limiting consumption to:

• No more than one drink per day for women.
• No more than two drinks per day for men.

“If you want to prevent cancer, though, there’s really no safe amount of alcohol,” Dr. Kamath says. “I urge people to drink as little as they can, preferably one or two drinks per week at the most. Even swapping an alcoholic drink with a nonalcoholic option can make a big difference.”

Quitting alcohol won’t decrease your risk overnight, particularly if you’ve used alcohol for many years. But it will keep your risk from rising further — and research shows that sustained quitting is associated with lower cancer rates.

There are other important steps you can take to prevent cancer, too, including:

• Eating a balanced diet
• Maintaining a healthy weight
• Not smoking

“Up to half of all cancers are thought to be preventable,” Dr. Kamath says. “Knowing that may give people a sense of control and responsibility for their health.”

If you have trouble quitting or scaling back on alcohol, talk to a healthcare provider. They can help you find the support you need to start reducing your risk of cancer.