Tobacco, Alcohol Raise Cancer Risk
The corner bar is no longer filled with smoke; even drug treatment centers are going smoke free. But the alcohol-tobacco connection still exists. Drinkers smoke, smokers drink; and both pay a price.
Smoking is a well known factor for many cancers, most notably lung and pancreatic but also stomach, kidney, bladder, colorectal, cervical, uterine and ovarian. It is also often a factor in acute myeloid leukemia. Alcohol is associated with liver and breast cancers. And both tobacco and alcohol have been linked strongly to cancers of the mouth and throat, including lip, oral cavity, pharynx, esophagus and larynx.
Tobacco contains more than 34 known carcinogens, and the risk comes not only with cigarettes but also cigars, pipes and smokeless tobacco. Smoking accounts for about 30 percent of all cancer deaths and 87 percent of those caused by lung cancer.
Alcohol is most closely linked with liver cancer. Carcinogens and toxins, as well as drugs such as alcohol are metabolized by the liver, and heavy use of alcohol over time limits its ability to disable them. For similar reasons, it may influence other cancers as well.
Alcohol is an irritant that can lead to inflammation and leave cells vulnerable to cancer. Alcohol also reduces levels of folate and other important nutrients and raises levels of estrogen, which, in turn, could affect a woman’s risk of breast cancer.
In some cases, particularly with oral cancers, the combination may be more hazardous than either substance on its own.
ORAL CANCERS: The link between tobacco, alcohol and oral cancers is fairly straightforward. In Utah, populated largely by Mormons whose religion calls for abstinence from both tobacco and alcohol, the rate of oral cancers is the lowest in the country. And these cancers are rarely found in developed countries where smoking and drinking are not prevalent.
Researchers have found that the risk for oral cancers rises greatly with the amount of alcohol consumed. A study of non-smokers in Italy and Switzerland found that subjects who consumed five or more drinks a day had a risk five times that of non-drinkers.
Of Americans diagnosed with oral cancer, about 75 percent have used tobacco products. Since most were also drinkers, it is hard to sort out which is the greatest risk. But they seem to act together.
Some experts believe that this may be because alcohol has a dehydrating effect on cells that it touches on the way down the throat. These cells are then made more vulnerable to the carcinogens in tobacco smoke.
Some doctors have noted that patients with cirrhosis of the liver often display changes in the tissues of the mouth and throat–a smooth, glossy appearance–that could also account for their increased risk of oral cancer.
PANCREATIC CANCER, one of the deadliest of cancers with mortality rates approaching 100 percent, is believed to be caused by some combination of genetic mutations and lifestyle factors such as smoking, a diet high in animal fat and excessive intake of carbonated soft drinks.
The association with tobacco is strong and fairly well known but still not as strong as the link between smoking and lung cancer.
In cultures where drinking habits are low to moderate, a link between pancreatic cancer and alcohol has not been found. But recent studies suggest that persons who drink heavily have an increased risk.
Heavy drinkers often develop pancreatitis, inflammation of the pancreas, probably caused by oxidative damage. This could leave the organ more vulnerable to cancerous changes.
A multi-center study published in the American Journal of Gastroenterology [2012] found a dose-related increased risk for early pancreatic cancer among both smokers and drinkers. Heavy smokers and drinkers tended to be diagnosed about five years earlier than other patients. The effects of both alcohol and tobacco were deleted, though, after 10 years of abstinence.
BREAST CANCER: An analysis of data from 53 epidemiological studies [British Journal of Cancer, 2002] suggested that about four percent of breast cancers in developed countries can be attributed to drinking of alcoholic beverages. In developing countries, where alcohol consumption was low, the effect of alcohol was negligible.
The same study concluded that the relative risk increased by 7.1 percent for each additional 10 grams of alcohol consumed per day.
It’s believed that most of the increased risk associated with alcohol comes from the hormonal changes it creates. By contrast, smoking tends to lower estrogen production, but this benefit is countered by a carcinogenic effect.
Some epidemiological studies have found that even moderate drinking–one or more drinks a day is associated with a higher risk of breast cancer, and some experts are recommending abstinence, particularly for women at risk.
Recent thinking, however, is that reported levels of alcohol consumption used in epidemiological studies do not adequately take into account pattern and timing of drinking. Binge drinking, four or more drinks on a Saturday night and none the rest of the week, does not qualify as moderate drinking, even though the total consumed may be relatively low. Blood alcohol content becomes higher, and the metabolism of alcohol changes. This pattern of drinking, particularly during youth, is believed to be a bigger risk than having one or two drinks a day in later life.
At any rate, moderate every day drinking has been found to have health benefits. An American Cancer Society study that followed half a million middle aged women for about 20 years found that mortality rates were 20 percent lower for women who consumed one alcoholic drink per day compared to those who never drank.
SO WHAT SHOULD YOU DO? With tobacco, there is no question: the health risks are great enough that you should quit. If you’re a non-smoker and a moderate drinker (one or two drinks a day) with no special cancer risks, you should probably continue what you’re doing.
Heavy drinking and binge drinking are another matter. In addition to the risk of alcoholism and its many related problems, heavy drinkers have an increased vulnerability to many cancers, particularly when drinking is combined with smoking, as it often is.
REFERENCES:
“Alcohol, diet and pancreatic cancer risks,” New York Times, June 11, 2010.
“Alcohol and tobacco,” About.com Alcoholism.
American Cancer Society, “Pancreatic cancer,” last medical review January 28, 2013.
American Cancer Society, “Tobacco and cancer.”
American Cancer Society, “Alcohol use and cancer,” last medical review January 12, 2012.
Michelle A. Anderson, “Alcohol and tobacco lower the age of presentation in sporadic pancreatic cancer in a dose-dependent manner,” American Journal of Gastroenterology, 2012;107(11):1730-1739.
“Cancer survival: pretreatment alcohol, tobacco, fruit, exercise habits linked to head and neck cancer survival,” Science Daily, April 10, 2009.
“Drinking alcohol,” BreastCancer.org, last modified September 17, 2012.
Collaborative Group on Hormonal Factors in Breast Cancer, “Alcohol, tobacco and breast cancer–collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease,” British Journal of Cancer, 2002;87:1234-1245.
Stephanie Grimes, “Alcohol consumption boosts cancer death risk, study says,” Science and Innovation, February 27, 2013.
Nick Mulcahy, “Link between pancreatic cancer and alcohol, tobacco use,” CME, American Journal of Gastroenterology, August 28, 2012.
National Institute on Alcohol Abuse and Alcoholism, “Scientsits rethink alcohol/breast cancer relationship,” October 16, 2012.
I dos Santos Silva, “Alcohol, tobacco and breast cancer: should alcohol be condemned and tobacco acquitted?” British Journal of Cancer, 2002;87:1195-1196.
R. Talamini, et al, “Tobacco smoking, alcohol consumption and pancreatic cancer risk: a case control study in Italy,” European Journal of Cancer, January, 2010.
“Why drinking alcohol is linked to breast cancer,” ScienceDaily, April 23, 2012
04/16/2013
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