Electronic Cigarettes May Still Pose Bladder Cancer Risk

At the recent American Urological Association’s Annual Meeting, findings from a pilot study done at the University of Pittsburgh Medical Center reported a potential link between e-cigarette use and bladder cancer.

In a statement, Sam S. Chang, M.D., M.B.A., who moderated the press session during which this study was presented, commented, “We’ve known traditional smoking raises bladder cancer risk, and given the surge in popularity of e-cigarettes, it’s imperative we uncover any potential links to e-cigarette smoke and bladder cancer.”

While e-cigarettes may be safer than traditional cigarettes, the composition of the liquids in these devices are complex and unregulated. There is a wide variety of formulas and some may contain known bladder carcinogens such as nitrosamines, formaldehyde, acrolein, metals and acetaldehyde.

The study reported that the urine samples of e-cigarette users contained some of those known carcinogens.

In an interview with CURE, senior researcher on the study, Tatum Tarin, M.D., commented, “One of the biggest impetuses for this study is that we know that e-cigarettes and vaping is a useful tool for people to stop smoking, sort of a safe alternative.

"There's been a 900% increase in e-cigarettes and vaping in kids, that wouldn't be smoking otherwise. What we were trying to show is that in kids who are non-smokers, this is not exactly a safe thing, or at least we don't know the full safety profile of electronic cigarettes and vaping."

Researchers collected urine samples from thirteen e-cigarette users and ten non-smoking, non e-cigarette using controls. Using liquid chromactography-mass spectrometry, they tested the samples for five molecules that are known to be bladder carcinogens and are either present in traditional cigarettes or common solvents believed to be used in some e-cigarette formulations. Those molecules are: benzanthracene, benzopyrene, 1-hydroxypyrene, o-toluidine, 2-napthylamine. The patients self-reported abstinence from traditional cigarettes for at least six months prior to the specimen collection.

Twelve of the thirteen samples from e-cigarette users tested positive for two of the carcinogenic compounds: o-toluidine, and 2-napthylamine. All samples from the ten control patients tested negative for the five molecules. The other three carcinogens were not identified in any samples.

Tarin explained that the two molecules identified have “been studied for a very long time, mostly in environmental exposures. They’re known to be in people who smoked tobacco and used conventional cigarettes. O-toluidine, and 2-napthylamine are known to be bladder cancer-causing agents.”

Additionally, nine of the thirteen e-cigarette users reported being long term nonsmokers, greater than twelve months.

Tarin also pointed out that the thirteen e-cigarette users were surveyed and “every single one thought there were no harmful, deleterious side effects in electronic cigarettes. While they probably are a safer alternative to smoking, they are not completely safe. And that’s what we’re trying to show here. Compared to our control group of non-smoker, non-electronic cigarette users, [e-cigarette users] had higher levels of these bladder carcinogens.”

Researchers determined that further studies should clarify the safety profile of e-cigarettes and their contribution to the risk of bladder cancer, given the higher concentration of carcinogenic compounds in the urine of the e-cigarette users in this study. “It will be important to try and quantify in the long-term, to see what is the actual effects on bladder cancer, or patients who have bladder cancer,” Tarin noted. “The issue is, there are kids that are doing this. We don’t want to be 50 years down the road, saying, ‘Oh my god, we thought this was safe, but actually there’s a problem.’”