That cell may then, over time, change in it's growth characteristics or in its internal control mechanisms. At a later time, another event occurs, possibly another environmental exposure or a spontaneous mutation. Maybe it takes several of those events over time. Maybe it takes many to ultimately cause a cancer. While conceding it may be the best current hypothesis, Hansen considers it far from definitive.
Smoking is related to more cancers, certainly lung cancer being the most obvious.
I must say that that incidence of cancer in general would be significantly reduced without cigarettes. According to Schuetz, a patient's positive view toward their situation can make their treatment easier to bear and more effective. They can feel comfortable with that. It's important that they feel comfortable discussing other aspects of their lives, like their spouse or children having trouble dealing with their diagnosis of cancer. It's important that people know that they can connect with other people who are able to help them and give them support.