The more people smoke, the longer they smoke, and the
earlier they start smoking, the more likely they are to develop lung cancer.
Smokers of two or more packs a day have lung cancer mortality rates 15 to 25
times greater than non-smokers. If smokers stop smoking before cancer has
started, their lung tissue tends to repair itself, even if there were already
precancerous changes. Former smokers who haven’t smoked for 15 or more years
have lung cancer mortality rates only somewhat above those for non-smokers.
