Who told you that there is any connection between vaping and cancer? It's tar building up in your lungs from burning processed tobacco that is the source of lung problems like cancer. You aren't burning anything when you vape. (Well not unless you are doing something really really wrong...)
My MD's - GP, allergist, cardiologist - none of them have a problem with vaping or have expressed any concern that it poses health risks. However - they all have a big problem with smoking.