E-cigarettes are likely to cause lung cancer and oral cancer

A report by the Clinical Oncology Society of Australia (COSA) Working Group on “E-cigarettes and Cancer – a qualitative assessment”, which included Professor Bernard Stewart (UNSW, Chair) and Adjunct Associate Professor Freddy Sitas (ICFHS) was published on 5 August 2025.  After reviewing the existing laboratory, animal and human evidence, the Working Group concluded that nicotine-based e-cigarettes contain known carcinogens, “Nicotine-based e-cigarettes are likely to be carcinogenic to humans who use them, and “E-cigarettes are likely to cause lung cancer and oral cancer”.  This finding is a call for good epidemiological data to provide quantitative assessments on the level of risk.  A USA-based epidemiological study published in 2024, shows users of both e-cigarettes and tobacco are about four times more likely to develop lung cancer (on top of their already 13-fold increased risk from smoking tobacco); and over 97% of those who vaped were smokers, i.e. unable to quit either habit. The current evolving findings are particularly relevant to those who are attempting to use e-cigarettes to quit smoking.