Clearly there are several other factors involved, but just because that is true that does not mean that they are equally likely. This is wishful thinking and can obviously be used to justify anything.

Smoking IS a major cause for oral cancer, there is no if, and, or but about it. It is also something you can control yourself. You cannot do much about your genetic predisposition. The fact that he smokes and has cancer now means that it it highly likely that this was the cause. In the unlikely event that it was not.... continued smoking will retard the healing process and can also cause brand new cancers and other health issues. And since he, like many of has already gotten it, it is also clear that the immune system already screwed up once! There are already enough people who are doing the right things and who unfortunately still do not make it. Smoking makes the long term prognosis poor statistically.

The message is very clear.

M