Electronic cigarettes, vaping-related lung injury and lung cancer: where do we stand?

Electronic cigarettes have been considered a promising alternative to nicotine replacement products to help heavy tobacco smokers quit smoking. They work thanks to a heating coil causing evaporation of the liquid rapidly followed by cooling, thus creating an aerosol, a completely different mechanism from the combustion of tobacco in traditional cigarettes. The term 'vaping' indicates the use of electronic cigarettes or other devices to inhale heated, aerosolized nicotine, or other substances like cannabidiol, tetrahydrocannabinol, or butane hash oils together with solvents, mainly propylene glycol and vegetable glycerine or their combination. A very fast increase of vaping among adolescents has been observed since electronic cigarettes and other vaping devices first appeared. Although electronic cigarettes have been advocated as a short-term cessation aid for tobacco smokers or as a long-term alternative, there is the concrete risk that they can be perceived by young nonsmokers as a less dangerous alternative to tobacco smoking, thus stimulating nonsmokers to start smoking rather than helping heavy tobacco smokers to quit smoking. Moreover, several cases of exogenous lipoid pneumonia and diffuse alveolar hemorrhage with proven alveolar injury, as well as vaping-associated bronchiolitis obliterans, have been recently reported among electronic cigarette smokers, with severe clinical impact, thus posing the risk of the life-threatening toxic potential of vaping. At the moment, no definitive assessment can be made about the efficacy of electronic cigarettes as a smoking cessation aid, and further studies are required about vaping-related life-threatening acute lung injury.