Alcohol causes about 3.5% of all U.S. cancer deaths and 15% of breast cancer deaths, a new report says. Most of the increased cancer risk is among people who have more than 3 drinks a day. But those who had an average of 1.5 drinks a day accounted for nearly one-third of the deaths, the report says. Researchers from the National Cancer Institute did the study. It's the first thorough look at the links between alcohol and cancer in more than 30 years. They used information from several databases and surveys. The study estimated that alcohol caused 18,000 to 21,000 cancer deaths in 2009. Breast cancer was the most common type linked with alcohol in women. Among men, cancers of the mouth, pharynx, larynx and esophagus accounted for the most deaths. An expert interviewed by the New York Times News Service said the report failed to account for the effect of drinking patterns. Binge drinking is thought to be riskier than drinking small amounts frequently. The American Journal of Public Health published the study online February 14. The Times news service and HealthDay News wrote about it.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

A little alcohol is good for the heart. That message has received plenty of attention. But what about cancer risks from alcohol?

According to these authors, even moderate drinking increases the risk of developing some cancers. And your chance of dying from those types of cancers gets higher as you drink more.

About 4% of cancer deaths worldwide are related to alcohol use. Until now, a major study of alcohol-related cancer deaths in the United States had not been done in more than 30 years.

Researchers from the National Cancer Institute decided to take on the task. They analyzed many studies and large information databases. Based on all of this information, they calculated that alcohol causes 3.5% of U.S. cancer deaths. That's close to 20,000 cancer deaths each year from alcohol use.

Suggested ways that alcohol causes more cancer include:

• Toxic effects of chemicals produced when the body breaks down alcohol
• Increased production of oxygen radicals, which can damage cells
• Changes in the way the body handles vitamin B6 (folic acid)
• Higher levels of estrogen, which can increase the risk of breast and other female cancers
• Interaction with other cancer-causing agents, such as tobacco, to make them more harmful

The types of cancer most influenced by alcohol use are different for men and women. For men, it's primarily a higher risk of mouth, throat and esophageal cancer. For women, it's an increased risk of breast cancer.

But what about the reduced risk of heart-related deaths in people who drink a little alcohol compared with those who don't drink at all? A recent detailed analysis looked at 84 of the best studies related to the alcohol and heart connection. The studies included more than 2 million men and women. Researchers kept track of them for an average of 11 years.

Compared with no alcohol use, moderate alcohol use:

• Reduced the risk of a new diagnosis of coronary artery disease by 29%
• Reduced the risk of dying from a heart attack by 25%
• Reduced the risk of dying from any heart or blood vessel disease by 25%

Most importantly, the study found that moderate alcohol use reduced the risk of dying from any cause by 13% compared with no alcohol use. This included cancer deaths.

What Changes Can I Make Now?

We should not ignore these facts:

• Alcohol can cause cancer.
• The more alcohol you drink, the higher your risk of cancer.
• If you smoke, alcohol use significantly increases your cancer risk above and beyond the risk from smoking.
• Even very moderate use of alcohol is linked with a higher risk of some cancers, especially breast cancer in women.

But what about the reduced risk of dying from heart disease? Heart and blood vessel diseases are still the No. 1 cause of death in the United States and most developed countries.

If you don't drink alcohol now, there's no reason to start. But also don't worry if you occasionally have a drink.

If you do enjoy alcohol, the limit is two drinks per day for men and one per day for women. You don't get any extra heart protection by drinking more. And your risk of cancer and lots of other problems rises dramatically with higher consumption.

Should a woman at higher than average risk of breast cancer or a woman just very worried about developing breast cancer stop drinking? We don't know the answer to that question. It would depend on whether the woman also has factors that increase her risk of heart disease. With an increased heart disease risk, the answer might be to continue moderate alcohol use.

What Can I Expect Looking to the Future?

With advances in genetics, we will be able to predict more accurately who can safely drink alcohol in moderation and who should avoid it completely.