Double trouble: Tobacco and alcohol combine to elevate cancer risk

a man putting out a cigarette in an ash tray while drinking a beer
Tobacco and alcohol each increase the risk of several cancers. Combined, these two habits significantly increase the risk of cancers in the aero-digestive tract.

For many people, smoking and drinking go together like bacon and eggs or hot dogs at a baseball game. But when it comes to cancer risk, Stephen Lynch, MD, Primary Care and Intake Physician at our Phoenix hospital, compares alcohol and tobacco to a more volatile pairing. "It's gasoline and matches," he says. Tobacco and alcohol alone each increase the risk of several cancers. Combined, these two habits significantly increase the risk of cancers in the aero-digestive tract—the lips, mouth, larynx, pharynx, throat,  esophagus and colon. "It is well known that smoking and drinking at the same time significantly increases the risk of many cancers," says Wissam Jaber, MD, Director of Interventional Pulmonary Medicine at our Phoenix hospital. 

You are multiplying your risk not only twofold, but many-fold when you do the two together.” - Wissam Jaber, MD, Interventional Pulmonologist

Every cigarette damages the body, and in many ways. "Just one cigarette can increase your risk of cardiovascular disease," Dr. Jaber says. "It increases your blood pressure, and adds cumulatively to the risk of cancer over time." Each time a smoker inhales a lit cigarette, a chemical chain reaction erupts that creates dozens of carcinogenic compounds. These compounds in the cigarette smoke are sucked through the lips, past the tongue and mouth, down the throat and into the lungs, causing inflammation in all those body parts and exposing them to cancer-causing chemicals. Once in the lungs, compounds from the smoke are absorbed into the bloodstream and spread carcinogens to the rest of the body.

Smoking and drinking by the numbers

  • 20 percent of American adults, nearly 38 million people, are smokers.
  • 70 percent of American smokers, more than 26 million people, also drink.
  • 80 to 95 percent of alcoholics are smokers.
  • 70 percent of alcoholics are heavy smokers (more than one pack per day).
  • 80 percent of throat and mouth cancer in men and 65 percent of throat and mouth cancer in women are linked to the combination of smoking and drinking.
  • Sources: 2014 Gallup survey; National Institute of Alcohol Abuse and Alcoholism

Tobacco smoking "can cause cancer almost anywhere in your body" and is linked to 90 percent of all lung cancers, according to the U.S Centers for Diseases Control and Prevention. Cigarette smoking is the leading cause of preventable disease and death in the United States, contributing to more than 480,000 deaths every year. Tobacco smoke damages not just DNA, but also the proteins in cells that repair DNA damage. Smoking also interferes with a process called metabolic detoxification, in which cells neutralize some toxins and flush the harmless byproducts out of the body. "Tobacco is the no-brainer," Dr. Lynch says. "Everyone understands that now. But alcohol, because it does have some benefits with respect to cardiovascular risk reduction, people say it’s good for you."

Unlike cigarettes, not every drink is harmful. Moderate amounts of alcohol may help reduce the risk of stroke and cardiovascular disease. "But it's a fine line," Dr. Jaber says. "When you go beyond moderate use, it increases the risk of breast cancer, colon cancer, aero-digestive cancers and many other cancers." Moderate use is defined by the National Institutes of Health (NIH) and the American Heart Association as no more than two drinks a  day for men and one drink a day for women. Alcohol may increase cancer risk in several ways. It can cause inflammation in the liver and pancreas, raising the risk of cancer in those organs. When metabolized, alcohol produces a substance called acetaldehyde, which may stop cells from repairing DNA damage. "Alcohol is a carcinogen," Dr. Lynch says. "There really is no debate about that anymore. It is a cancer-causing agent, and the more you consume, the higher your risk."

What's a drink?

Alcohol enhances the effects of tobacco in several ways—for example, by increasing the production of certain enzymes that convert tobacco tar into carcinogens. Excessive drinking may also suppress the immune system, and smoking and alcohol combined may compound the inflammation caused by each. "It's not one plus one equals two," Dr. Lynch says. "There's a much more exponential synergy when you combine alcohol and smoking." People who drink and smoke are 15 times more likely to develop cancer in the mouth and throat than nondrinkers and nonsmokers, according to the NIH.

Some cancer patients may assume that they might as well continue bad habits like smoking and drinking, because the damage has already been done. Dr. Jaber says that’s a mistake. "We try to make an intervention on both aspects to reduce future risk and improve the outcome during cancer treatment by reducing inflammation caused by drinking and smoking," he says. Various studies have produced mixed results on the success of treating tobacco and alcohol addictions at the same time, but the NIH recommends that approach. "Treating co-occurring disorders remains a challenge," the NIH says. "However, evidence suggests that combining treatments might be the most effective way to address concurrent addictions."