pretty depressing stuff http://whyquit.com/whyquit/Memorial_2.html
140,000 Americans die every year from lung cancer, although 10% of lung cancer patients have no history of smoking. One thing that makes lung cancer unique and also so lethal compared to other cancers is how quickly the victim wastes away. In the case of late-stage lung cancer, for many people the transition from being an outwardly healthy and productive individual to being bedridden only takes a few months–that’s how virulent it is. Small cell lung cancer is the most aggressive, and such patients are most likely to die in this manner, whereas non-small cell is not quite as bad and is more amenable to surgery. COPD is also pretty bad, but tends to be much more chronic.
The risk between cigarettes smoked/day and lung cancer, somewhat counterintuitively, has a logarithmic relationship. This means that those who think they are meaningfully reducing their risk by ‘only’ smoking a pack a day instead of two, are doing themselves no favors. It makes scant difference whether you smoke 10 cigarettes a day or three packs a day. Making matters worse, although quitting reduces the risk of cardiovascular disease and stroke, accumulated lung cancer risk is irreversible (some have likened it to an escalator, where you can get off any time but you cannot go down). The most feared and lethal consequence of smoking, lung cancer, cruelly, is the one most impervious to quitting. According to studies, most lung cancer patients are former smokers. Anti-smoking guru Allen Carr and news anchor Peter Jennings are two well-known examples of individuals who quit smoking but died of lung cancer decades later.
For example, many if not most patients with a history of smoking quit decades before. In a retrospective study of 626 people with lung cancer treated at a tertiary-care facility in Southern California, 482 (77%) had a history of smoking. Of those, only 71 patients (14.7%) were still smoking at the time of their diagnosis. Of the remaining 411 patients, 245 (60%) had not smoked for a mean of 18 years, 8 of whom had quit 51 to 60 years earlier. The other 166 (40%) had stopped smoking within 10 years of their diagnosis.
“Sixty percent of our cohort developed lung cancer despite doing the right thing by stopping smoking over 1 decade ago,” according to the researchers.
The lag time from smoking to cancer is 20 years:
This is similar to asbestos exposure and the development of mesothelioma decades later. Once the particles enter the lungs, they sit there and cause irritation and abnormal cell growth, and eventually for some this leads to cancer.
Cigarettes are also more addictive than even hard drugs. The reason why smoking is so addictive is not because of the nicotine, but rather the delivery method, which is why vaping and nicotine replacement therapy tend to be ineffective.