Since President Richard M. Nixon declared a war on cancer more than 30 years ago, the battle still rages on several fronts. On the front lines are the continued attempts at finding ways to prevent the disease from occurring at all, and on this battlefield the debate over one primary target of prevention is engaged in heavy fire: tobacco. As the main cause of lung cancer, which kills more people in the United States than any other cancer, as well as implicated in a host of other cancers and ill health effects, smoking tobacco is under attack by physicians, public health policy makers, government officials, insurance companies, and all those taking up arms to prevent this deadly disease.
According to Michael J. Thun, MD, National Vice President of Epidemiology and Surveillance Research at the American Cancer Society, a number of policies have been effective in reducing tobacco use, such as increasing the price of cigarettes through excise taxes, restricting smoking in public places, and the use of counter-advertising that that has effectively reduced the uptake of smoking by children, cut back on per capita cigarette consumption, and denormalized tobacco use. Despite their proven effectiveness, however, inadequate implementation of these policies at the state and federal levels are impeding their success, he said.
Another strategy that is under intensive investigation is finding alternative products that may satisfy the smoker’s addictive needs while reducing the adverse effects of tobacco on their health. One alternative that has caught the attention of some public health officials is the possibility of reducing cancer risk in smokers by advocating the use of chewing tobacco (more aptly called snuff or smokeless tobacco, since the correct way to use these products is not to chew them but to place them snugly between the cheek and gums) in place of smoking. The rationale is based on evidence that shows decreased lung cancer mortality and other cancer risks in users of smokeless tobacco products with low nitrosamine content versus those who smoke. However, the downside is the potential oral health risks, including cancer, as well as the yet unknown systemic side effects of these products. How do oral specialists and other cancer experts feel about this question?
Oral Specialists and Other Experts Weigh In
I think it’s probably not a good idea to recommend one bad habit to replace another bad habit, said Terry Day, MD, a head and neck surgeon at the Medical University of South Carolina who has done research on oral cancer. I think there are many other ways to reduce the effect of smoking and lung cancer than switching to another tobacco product.
Erich M. Sturgis, MD, MPH, of the Department of Head and Neck Surgery at the University of Texas M.D. Anderson Cancer Center in Houston, put it just slightly differently. Should we recommend that morbidly obese individuals smoke to help them stop eating? he said, also advising that numerous pharmacologic and nonpharmacologic alternatives to smokeless tobacco are available to help people stop smoking.
For Dr. Day, one big unknown with switching to smokeless tobacco is how this would affect oral cancer risk. If we converted all of the smokers to chewers, I’m afraid our oral and pharyngeal cancer rates would increase, in addition to the number of people who have other oral health-related problems, he said.
His fears are not unfounded. A study published in the Lancet in 2004 by a panel of 19 scientists from seven countries on behalf of the International Agency for Research on Cancer concluded that smokeless tobacco causes both oral and pancreatic cancer in humans (Lancet 2004;5:708). According to Debbie Winn, PhD, of the Division of Cancer Control and Population Sciences at the National Cancer Institute (NCI), smokeless tobacco approximately quadruples the risk of oral cancer.
Although conceding that smokeless tobacco is linked to far fewer diseases and causes less mortality than smoking tobacco, Dr. Winn stressed that smokeless tobacco products are not harm-free.
The reason this debate is under way at all among health professionals is the dire consequences of smoking tobacco on health, and the need to find practical, effective ways of reducing their harm. Over the past several years, evidence has suggested that newer smokeless tobacco brands that have low nitrosamine content carry substantially less risk of lung cancer and other diseases associated with smoking. In 2004, an NCI-funded study based on expert opinion found that the median mortality risks relative to smoking with low-nitrosamine smokeless tobacco (LN-SLT) products were estimated to be 5% for total mortality, 2% to 3% for lung cancer, 10% for heart disease, and 15% to 30% for oral cancer (Cancer Epidemiol Biomarkers Prev 2004;13:2035-2042).
There was a strong consensus among public health experts that given the alternative of using LN-SLT or cigarette smoking, use of LN-SLT was a lot less dangerous compared to smoking-on the order of about 90% less risky, said K. Michael Cummings, PhD, MPH, Chair of the Department of Health Behavior in the Division of Cancer Prevention and Population Sciences at Roswell Park Cancer Institute in Buffalo, NY, one of the authors of the study, who added that this consensus was particularly strong in regard to lung cancer risk but less so for oral cancer risk.
Dr. Cummings thinks that health professionals, although well meaning, need to be better educated about the different risks posed by the different brands of smokeless tobacco brands. I think the data are compelling that tobacco with low nitrosamine content is less risky compared to [those with] high nitrosamine content, he said. In the US, Copenhagen and Red Rooster are really dirty products that probably should be banned. Arriva and Stonewall, two low-nitrosamine products, are probably not so different from a nicotine lozenge.
Given this, Dr. Cummings believes that smokeless tobacco is a viable alternative to smoking-with a caveat. I would only recommend smokeless tobacco as an alternative to smoking after exhaustively advising a smoker to quit smoking without medications or by using an FDA-approved stop-smoking medication, he said, adding that in my 26 years of helping smokers to quit, I only know of a few smokers who quit smoking by using smokeless tobacco.
For Dr. Thun, strategies that focus on harm reduction are distracting from the current strategies that are effective but not yet fully implemented. Thus the debate about ‘harm reduction’ seems premature, he said, and a distraction from other approaches the we know are safe and effective.
Do People Really Switch?
Another major argument against recommending smokeless tobacco as a viable alternative for smoking cessation is concern that smokers will not switch completely but perhaps will augment their smoking with chewing-for instance, by chewing in public places where smoking is banned and then smoking where they can.
Smokers who use these products to postpone quitting by assuaging their nicotine craving in settings where smoking is prohibited and then lighting up whenever possible, magnify their risk of lung cancer and other smoking-related diseases by prolonging the duration of their smoking, said Dr. Thun.
Dr. Winn agreed that there is insufficient evidence to determine if advising people to switch to smokeless tobacco is at all useful in getting people to quit smoking.
A more recent study published in 2006 by Dr. Cummings and his colleagues may offer some response to this question. In the study, a panel of experts looked at whether introducing a new LN-SLT product under strict regulations into the marketplace would reduce overall smoking prevalence. The study concluded that cigarette users would switch to smokeless with little change in overall tobacco use and with a limited degree of substitution of LN-SLT for cigarettes. If these results hold, the substantial reduction in health risks associated with LN-SLT use should yield a net public health benefit through reduced mortality (Addictive Behav 2006;31:1190-1200).
Such data may not be too readily accepted, however, given the strong suspicions about the motivations of tobacco companies to sell their products. The last time the US tobacco companies aggressively marketed smokeless products they stimulated a large increase in use of their products by adolescent males but very little switching among smokers, said Dr. Thun.
Dr. Cummings acknowledges the challenges of debating this issue given the lack of trust that consumers and health care professionals have in the tobacco industry. Both the smoked and smokeless industries have given away their credibility by lying to the American public about the risks and addictive nature of their products, he said.
Prevention of Oral Cancer for Smokeless Tobacco Users
Although there are currently no established guidelines for screening for oral cancer in people who chew tobacco, both Dr. Sturgis and Dr. Day recommend regular physical exams that include an examination of the mouth, throat, and neck. We still recommend that people at risk visit their dentist and physician at least twice a year, said Dr. Day.
And both would advise physicians to counsel their patients against using chewing tobacco in place of smoking tobacco. If we recommend that people switch to chewing tobacco, said Dr. Day, we may potentially be putting them in more risk of other problems that we are not yet aware of due to the effects of the numerous possibly toxic chemicals in these products.
According to Dr. Day, the utility of screening for oral cancer remains controversial, as most studies show no survival improvement in people who are screened versus those who are not.
©2007 The Triological Society