Electronic Cigarette Use and Risk of Bladder Cancer

People who use electronic cigarettes (e-cigarettes) may have similar carcinogens in their urine as cigarette smokers that are linked to bladder cancer, according to study findings published in European Urology Oncology.

“Smoking is the No.1 modifiable behavioral risk factor for bladder cancer,” Dr. Marc Bjurlin, associate professor of urology in the UNC School of Medicine at the University of North Carolina Lineberger Comprehensive Cancer Center, said in a press release.

Researchers from UNC Lineberger and NYU Langone Health reviewed 22 different studies published since 2015 and included 1,259 participants. Each study analyzed the urine of e-cigarette users or other tobacco products with a goal of checking for evidence of cancer-linked compounds or biomarkers of those compounds. Carcinogens are substances that can cause cancer in living tissue.

They found 40 different parent compounds that can be processed in the body to produce 63 different toxic chemicals or carcinogenic metabolites, which are substances that remain in the body after processing, according to the study findings. Six of the chemicals found have a strong link to bladder cancer, the researchers explained. They include pyrene, naphthalene, fluorene, phenanthrene, o-toluidine and 2-naphthylamine.

“This systematic review summarizes the currently available data about the presence and levels of excreted urinary biomarkers related to e-cigarette exposure,” the researchers wrote. “The 22 included studies demonstrate differences in biomarker levels among nontobacco and e-cigarette users, as well as persistent presence of worrisome biomarkers in patients who have ‘switched’ from combustible cigarettes to e-cigarettes.”

Although the Food and Drug Administration and Centers for Disease Control and Prevention have warned about health risks of vaping, they haven’t been definitively characterized, Bjurlin explained.

“The first and foremost side effects that we’re seeing from electronic cigarette use are lung and pulmonary related,” Bjurlin said. “We won’t see the side effects for these other kinds of carcinogenic pathways until much later down the exposure pipeline.”

The researchers noted limitations to the study, such as not knowing the levels of all the cancer-causing substances in the urine and having participants who smoked and vaped e-cigarettes.

“Although there is no definitive case yet linking bladder cancer to vaping, it may be reasonable to suspect that decades down the road after exposure to these byproducts, people who vape may be at risk of developing bladder cancer,” he said.

Bjurlin plans to lead a study that will examine carcinogens in the urine of e-cigarette users, smokers and non-users.

“This finding shows us that people who vape will be exposed to a variety of different carcinogens,” Bjurlin said. “People who have decades of exposure to these carcinogens from vaping may be at risk for developing malignancies, especially bladder cancer.”