I take your point and would say that smoking most definately can give you cancer and can also create what is called pre cursor damage to lungs, mouth, tongue. This type of damage can be where cancer starts in future and that cancer can start elsewhere in the body but may also show up at those precurser spots. I am including smoking Marijuana in that as well. So many people smoking Marijuana think they will never get cancer. Lots of fit people who have never smoked get cancer including me. I smoked 35 years ago and none since and I was diagnosed with throat cancer over a year ago. I am clear now but you are never clear only till the next check with a PET scan done 6 monthly.
I had lengthy discussion with ENT and Oncology experts about this. In short they dont know what spurs cancer to start but warn that smoking and alcohol are two big factors. One of the first things a doctor asks when you get checked for cancer is have you ever smoked tobacco, have you ever smoked Marijuana.
