There are a couple of things going on. 1. the vapor from these e-cigs contains much finer particles than in smoke, so they can penetrate deeper into tissue and more easily cross the capillary bed and go into the blood stream. 2. People are vaping things lie THC, CBD oil, and even things like heroin. 3. People are modifying the device so you get a much higher concentration of product (dabbing).
So if you are just using it for nicotine and don’t modify it doesn’t it make sense that it would still make you more susceptible to cancer?