The Role of Smokeless Tobacco in Smoking Cessation

With approximately 6 million users, smokeless tobacco has received considerable scrutiny as a risk factor for oral cancer. We review the relationship between smokeless tobacco use, white callous-like patches in the mouth called keratosis, and oral cancer. Although relatively common, several features of smokeless tobacco keratosis make it less likely to be precancerous than leukoplakia (literally "white patch") associated with smoking. Previous research has demonstrated that the relative risk (RR) of oral cancer with smokeless use is 4.2, about half of the risk from smoking (RR= 10-15). Mortality data from populations with sustained high frequency smokeless tobacco use do not support the mistaken prediction of an epidemic of oral cancer with increasing smokeless use. For example, Sweden has been the world's largest per capita consumer of smokeless tobacco throughout the 20th century, and no oral cancer epidemic has resulted. On the contrary, a retrospective study of 200,000 male snuff dippers in Sweden found only one case of oral cancer per year. This is in marked contrast to most other European countries where smokeless use is essentially nonexistent and where increases in oral cancer mortality have mirrored earlier increases in cigarette consumption.

Recommending a switch from cigarette smoking to smokeless tobacco has elicited ethical concerns from some anti-tobacco activists. It is important to remember that recommendations from health professionals almost always have a measurable risk/benefit ratio. For example, radiation and chemotherapy are standard cancer treatment options, even though they present risks, some as severe as the development of a second cancer. The same principle applies to strategies in preventative medicine. For example, tamoxifen, an estrogen receptor antagonist, is under study by the National Cancer Institute as a preventive measure for primary breast cancer in high risk patients. While tamoxifen may reduce the risk of developing breast cancer, it increases ( by 7.5-fold) the risk of developing uterine cancer. However, the NCI considers the risk/benefit ratio low enough to continue the study. Smokeless tobacco is an excellent risk-reduction strategy because it reduces the smoker's risk for all tobacco-related illnesses and produces no new risks.