Longkanker

Smoking

Following an increase in smoking in the population, the rate of lung cancer death increases. Source: NIH.

Smoking, particularly of cigarettes, is by far the main contributor to lung cancer.^[32] Across the developed world, almost 90% of lung cancer deaths are caused by smoking.^[33] In the United States, smoking is estimated to account for 87% of lung cancer cases (90% in men and 85% in women).^[34] Among male smokers, the lifetime risk of developing lung cancer is 17.2%; among female smokers, the risk is 11.6%. This risk is significantly lower in nonsmokers: 1.3% in men and 1.4% in women.^[35] Cigarette smoke contains over 60 known carcinogens,^[36] including radioisotopes from the radon decay sequence, nitrosamine, and benzopyrene. Additionally, nicotine appears to depress the immune response to malignant growths in exposed tissue.^[37]

The length of time a person smokes (as well as rate of smoking) increases the person's chance of developing lung cancer. If a person stops smoking, this chance steadily decreases as damage to the lungs is repaired and contaminant particles are gradually removed.^[38] In addition, there is evidence that lung cancer in never-smokers has a better prognosis than in smokers,^[39] and that patients who smoke at the time of diagnosis have shorter survival times than those who have quit.^[40]

^{bron: http://en.wikipedia.org/wiki/Lung_cancer}