E-Cigarettes: Unstandardized, Under-Regulated, Understudied, and Unknown Health and Cancer Risks.

E-cigarettes have the ability to deliver nicotine in a manner that is similar to, and, theoretically, safer than, combusted tobacco. However, these devices are extremely heterogeneous and regulation has struggled to keep up with their rapid evolution. A compilation of early data suggest that e-cigarettes may contain numerous toxic substances, including known carcinogens. However, there are few data available on the short- and long-term health effects of e-cigarettes, including any potential effect on cancer risk. Until more is known, e-cigarettes should not be considered a safe alternative to combusted tobacco use. ©2019 American Association for Cancer Research.