September 22, 2014

expert reaction to e-cigarette use among patients with cancer

Researchers publishing in the journal Cancer have reported their findings that e-cigarettes may not help cancer patients stop smoking.

Professor Robert West, Editor-in-Chief of Addiction and Director of Tobacco Research at UCL, said:

“This is a well-designed study to describe what happens to smokers who also use e-cigarettes and who have a strong incentive to stop smoking. Unfortunately, the headline in the press release gets it all wrong: the study could not address whether using an e-cigarette in an attempt to stop is useful or not because the sample could consist of e-cigarette users who had already failed in a quit attempt, so all those who would have succeeded already would be ruled out. Within this sample, it looks as though people who used e-cigarettes at baseline might be less likely to be abstinent at follow up after adjusting for a range of potential confounding factors including FTND (a measure of cigarette dependence). Now one could argue that FTND is a relatively weak measure of dependence but the data set up the hypothesis that dual use of e-cigarettes and conventional cigarettes may, for whatever reason, reduce the chances of subsequently becoming abstinent.

When you take this together with evidence from a previous study on use in a quit attempt, a theory is beginning to emerge that perhaps e-cigarettes can be in some cases be good at substituting for cigarettes and promoting complete abstinence by virtue of their superficial similarity to cigarettes, but if abstinence is not achieved (or sought) they might undermine quitting for precisely the same reason – their similarity to cigarettes inhibits deconditioning of the stimuli associated with smoking and the nicotine reward.

If this hypothesis is correct then the advice to smokers might be along the lines of – consider e-cigarettes for complete substitution but if that does not work then use a patch or other nicotine product for partial substitution (because these have shown a clear prospective association with quitting when used for smoking reduction).

We should remember that we are in the early days of researching e-cigarettes and be careful not to make sweeping statements until we have more good studies.”

Professor Peter Hajek, Director of the Tobacco Dependence Research Unit at Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, said:

“The study data do not justify the conclusions presented as the main finding. The authors followed up smokers who tried EC but did not stop smoking, and excluded smokers who tried EC and stopped smoking. Like smokers who fail with any method, these were highly dependent smokers who found quitting difficult. The authors concluded that EC was not helpful, but that would be true for any treatment however effective if only treatment failures were evaluated.

There are other problems, such as uncertainty as to whether these smokers tried EC only once or used them for a few days or weeks and for what purpose, and presenting smokers who used EC, possibly only once 13 months ago, as if they were using them throughout the year. It is odd that in a study focusing on EC use, no data are provided on whether the participants actually used EC during the year of evaluation.”

“Electronic cigarette use among cancer patients: Characteristics of e-cigarette users and their smoking cessation outcomes” by Sarah P. Borderud et al. published in Cancer on Monday 22 September 2014.

Declared interests

Prof Peter Hajek:

“I have no links with any tobacco or e-cigarette manufacturers. My research into the safety and effects of e-cigarettes is funded by UKCTAS, MHRA and NIHR.”

Prof Robert West:

“I have not and will not accept any kind of funds, payments or hospitality from companies that make e-cigarettes because of the risk of being perceived as tainted on that count. I undertake research and consultancy for companies that manufacture smoking cessation medications and licensed nicotine replacement products. My salary is funded by Cancer Research UK.”