AUA 2017: Studies Examine Bladder Cancer Risk and Mortality in E-Cigarette and Traditional Smokers

Key Points

  • Smoking more packs of traditional cigarettes per day was associated with an increased risk of mortality among patients with bladder cancer.
  • Urine from 92% of e-cigarette users tested positive for two of the five carcinogenic compounds.
  • E-cigarette smoke induced tumorigenic DNA damage in bladder mucosa, and nicotine, nitrosamine, and formaldehyde also induced the same types of DNA damage in human urothelial cells, as well as inhibited DNA repair and enhanced mutational susceptibility.

Data presented at the 2017 Annual Scientific Meeting of the American Urological Association (AUA) showed harmful links between the use of e-cigarettes and bladder cancer risk, and associated the smoking of traditional cigarettes to a higher risk of mortality among patients with bladder cancer. Even a small decrease in the amount of traditional smoking a bladder cancer patient makes may help them live longer.

Use of electronic cigarettes (e-cigarettes) has grown drastically since first entering the marketplace more than a decade ago. While traditional cigarette smoking is a clear cause of bladder cancer, much less has been studied about the bladder cancer risk associated with e-cigarettes. Furthermore, there is limited information regarding the association between the amount of traditional cigarettes a patient with bladder cancer smokes per day and their mortality risk.

Smoking Intensity as a Predictor of Survival in Bladder Cancer Patients

In a study conducted by Sávio et al (Abstract MP04-18), survival rates were compared between more than 14,000 smoking adults with bladder cancer living in Florida between 1981 and 2009. Median and 5-year overall survival rates were compared between patients who smoked less than one pack of cigarettes a day, to those who smoked one to two packs per day and those who smoked more than two packs per day.

Results showed:

  • Smoking more packs per day was associated with an increased risk of mortality among patients with bladder cancer.
  • Patients smoking a minimum of one–two packs per day were significantly more likely to have a higher risk of mortality compared to patients that smoke less than one pack per day.
  • Even a small reduction in the amount of smoking a patient makes may potentially allow them to survive longer with bladder cancer.

Evaluation of E-Cigarettes Users Urine for Known Bladder Carcinogens

In a study conducted by Fuller et al (Abstract MP88-14), researchers compared the urine of e-cigarette users to that of nonsmokers. Urine samples were examined for five known bladder carcinogens that are either present in traditional cigarettes or common solvents believed to be used in some e-cigarette liquids.

The users were mostly male, with an average age of 39 years old. The nonsmokers had abstained from traditional cigarettes for at least 6 months prior to the test.

Results showed:

  • Urine from 92% of e-cigarette users tested positive for two of the five carcinogenic compounds.
  • Further study is needed to clarify the contribution e-cigarettes make to the development of bladder cancer, given the greater concentration of carcinogenic compounds in the urine of e-cigarette users in this study.

E-Cigarette Smoke is Potentially Carcinogenic

E-cigarettes have been advertised as a way of delivering the stimulating effects of tobacco smoke, without the harmful health risks. Since 90% of inhaled nicotine is excreted to urine, New York University researchers set out to examine if e-cigarette smoke induced DNA damage in bladder mucosa (Abstract PNFBA-11). Researchers also looked at the effect of nicotine and its metabolites, nitrosamines, and formaldehyde on DNA repair and mutational susceptibility in cultured human urothelial cells.

Results showed:

  • E-cigarette smoke induced tumorigenic DNA damage in bladder mucosa.
  • Nicotine, nitrosamine, and formaldehyde also induced the same types of DNA damage in human urothelial cells, as well as inhibited DNA repair and enhanced mutational susceptibility.
  • Nicotine can be nitrosatized in urothelial cells, then further metabolized into carcinogenic nitrosamines and formaldehyde.

Overall, researchers predicted e-cigarette smokers have a high bladder cancer risk.

Commentary

“These studies raise new concerns about the harmful impact of e-cigarettes on bladder cancer,” said Sam S. Chang, MD, MBA, Professor of Urologic Surgery at Vanderbilt Ingram Cancer Center. “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. This research underscores the importance of smoking cessation (of both traditional and e-cigarettes) for people with bladder cancer, and people looking to avoid it.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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