Electronic cigarettes are steadily rising in popularity as an aid to smoking cessation. A new study of cancer patients, however, suggests that patients using the devices are equally or less likely to quit smoking than those who do not use them. The scientists behind the research, which was published online in Cancer, the journal of the American Cancer Society, said their results raised doubts about whether e-cigarettes had any benefit in helping cancer patients – or anyone else – to give up smoking.
Uncertainty continues to surround electronic cigarettes, or e-cigarettes – battery-operated devices whereby the user inhales flavored vapor. Although they do not contain many of the harmful ingredients that traditional cigarettes contain, such as tar, they do contain nicotine. Past research has also found that some e-cigarettes contain toxic substances, and most could contain carcinogens. In fact, one recent study even found that secondhand smoke from e-cigarettes contains higher levels of toxic metals than conventional cigarettes.
The missing science and lack of regulatory standards has caused great concern among the public health community — and for good reason. Just last month, the BBC reported that E-cigarette liquid sold in England was found to contain a chemical called diacetyl, which is used to add butterscotch flavor to liquid tobacco. But although this substance is harmless to eat, it is extremely dangerous to inhale. The chemical is known to cause a serious condition called popcorn lung, or bronchiolitis obliterans, an irreversible disease which scars the lung and makes it impossible to breathe properly, and in many cases is severe enough to warrant lung transplantation. (The illness got its name because it primarily affects workers in popcorn factories, who are known to breathe in vast quantities of diacetyl, as well as ordinary people who eat a lot of popcorn.)
Furthermore, while e-cigarettes are often marketed as smoking cessation devices, it is not yet clear whether they are actually effective in that role. Earlier this year, researchers from University College London in the UK published a study claiming that e-cigarettes help smokers to quit. However, other research has challenged this theory. For instance, a study published in JAMA Internal Medicine found that there is no association between e-cigarette use and reduced cigarette consumption, suggesting that e-cigarettes should not be marketed as smoking cessation aids.
Quitting smoking
The benefits of quitting smoking are enormous — within minutes after quitting, the body has already begun to heal itself from the years of smoking-related damage, while significant improvements in circulation, respiratory functioning, and heart health are apparent within a matter of 2-3 months. Perhaps no one stands to gain more from quitting smoking than those already suffering from related diseases, such as cancer.
However, despite the well-documented risks to health that are posed by smoking, previous research has shown that smoking habits can continue long after a cancer diagnosis has been made. The authors of the new study state that approximately two thirds of smokers diagnosed with cancer continue to do so after diagnosis. This continuation is problematic, as smoking can cause new mutations among cancer survivors, resulting in secondary or further forms of primary cancer. Smoking can also reduce the effectiveness of some cancer treatments.
With the goal of filling in an important gap in the research on e-cigarette use, researchers from the Memorial Sloan-Kettering Cancer Center in New York City, NY, set out to investigate cessation outcomes for cancer patients using the devices. For the study, the team observed 1,074 cancer patients who smoked and were enrolled in a tobacco treatment program at a comprehensive cancer center between 2012 and 2013.
During this period, the researchers found a three-fold increase in e-cigarette use, from 10.6 percent of patients to 38.5 percent.
At the start of the study, e-cigarette users were found to be typically more nicotine dependent than non-users, had had more previous attempts at quitting, and were more likely to develop lung or head and neck cancers – cancers that are closely associated with cigarette smoking.
At follow-up, the e-cigarette users were found overall to be just as likely as the non-users to still be smoking. Seven-day abstinence rates for both e-cigarette users and non-users were very similar (excluding those patients who were lost to follow-up), sitting at 44.4 percent and 43.1 percent, respectively.
When examining their results as part of an intention-to-treat analysis, (a statistical procedure used to control for bias caused by participant drop-out, non-compliance, and missing outcomes), the researchers then found that e-cigarette users were twice as likely to be regular smokers of traditional cigarettes than non-users.
“Consistent with recent observations of increased e-cigarette use in the general population, our findings illustrate that e-cigarette use among tobacco-dependent cancer patients has increased within the past two years,” says Dr. Jamie Ostroff, one of the study’s authors. Importantly, however, the rise in e-cigarette use was not associated with an increased likelihood of cessation or even in a reduction in the rate of smoking. No findings were made to support oncologists suggesting e-cigarettes as an option to cancer patients as a means to quitting smoking.
E-cigarette uncertainty
“Controlled research is needed to evaluate the potential harms and benefits of e-cigarettes as a potential cessation approach for cancer patients,” says Dr. Ostroff, acknowledging that their study had its limitations. The study authors advise that their findings should not be interpreted to indicate that e-cigarettes will never help patients quit smoking, but that existing scientific evidence does not support their use in this population.
Further investigation is certainly warranted, says Dr. Ostroff, but “[i]n the meantime, oncologists should advise all smokers to quit smoking traditional combustible cigarettes, encourage use of FDA-approved cessation medications, refer patients for smoking cessation counseling, and provide education about the potential risks and lack of known benefits of long-term e-cigarette use.”
Other experts have called into question the reliability of the study. Prof. Robert West, director of tobacco research at University College London, UK, criticized the sample of patients used, as “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.”
However, caution regarding the use of e-cigarettes is advised by the American Cancer Society (ACS). On their website, they state that they cannot recommend the devices to help people quit smoking and that they will support legislation treating them like all other tobacco products until they are scientifically proven to be safe and effective.
Similarly, in August the American Heart Association (AHA) issued new recommendations stating that e-cigarettes should be subject to a federal ban for minors. In a statement, the AHA expressed concern that e-cigarette use among youths could lead to nicotine addiction and encourage use of conventional tobacco products. They also called for strict regulations on marketing of e-cigarettes and a ban on flavored vapors, citing research that demonstrates a link between the use of e-cigarettes and traditional smoking among adolescents.