Response to Stepanov et al
To The Editor:
NOT PEER REVIEWED The allegation by Stepanov et al1 that "regulation of TSNA levels in cigarette smoke should be strongly considered to reduce the levels of these potent carcinogens in cigarette smoke" ignores substantial evidence elsewhere in the literature that suggests that such regulation would do nothing to reduce cancer risk, and, in fact, might increase it.
Tobacco-specific N-nitrosamines (TSNA) represent two of a very large number of carcinogens in cigarette smoke. This being the case, there are two issues that should have been addressed prior to making the recommendation that TSNA levels be regulated.
The first is the question as to whether altering the blend of tobacco or curing techniques might increase the levels of other carcinogens. Stepanov et al do not consider this possibility.
The second relates to the findings of Pankow et al in their 2007 consideration of "Potentially Reduced Exposure Product" cigarettes.2 In this analysis, Pankow et al estimated the difference in lung cancer risk that could be achieved by eliminating 13 carcinogens from cigarette smoke, including the two major TSNAs. They concluded "there is little reason to be confident that total removal of the currently measured human lung carcinogens would reduce the incidence of lung cancer among smokers by any noticeable amount."
Given all of the above, the most logical conclusion would be that reducing TSNA concentration of cigarette smoke would be a waste of time and money. Advising smokers that one brand has a lower TSNA concentration than another brand to imply a lower risk of cancer would be fraudulent.
Joel L. Nitzkin, MD
1. Stepanov I, Knezevich A, Zhang L, Watson C, Hatsukami D, Hecht S. Carcinogenic tobacco-specific N-nitrosamines in US cigarettes: Three decades of remarkable neglect by the tobacco industry. Tob. Control 2011 20/May;Published online ahead of print. 2. Pankow J, Watanabe K, Toccalino P, Luo W, Austin D. Calculated Cancer Risks for Conventional and "Potentially Reduced Exposure Product" Cigarettes. Cancer Epidemiol Biomarkers Prev 2007;16(3):584-92.
Conflict of Interest: