Conclusion
The smoking status is likely to affect the clinical outcome
of both early and advanced stage lung cancers, and tobacco smoke-specific chemical compounds promote the progression of lung cancers via DNA alterations (which are possibly irreversible), and the modification
of various protein expressions (some of which are possibly reversible; Fig. 3). This may be confirmed by
clarification and evaluation of susceptibility to tobacco derived carcinogens. All oncologists, especially thoracic oncologists, must consider the relationship between smoking and shorter survival, and advise smokers to stop smoking to achieve optimal treatment results. The mechanisms involved in the smoking-related progression of lung cancer must be investigated further to find therapeutic targets for lung cancer as tobacco smoking is the most “certain” predisposing cause of lung cancer death.