Time's Dr. Sanjay Gupta answers questions on smoking and lung cancer:

If you quit smoking can you reduce or eliminate your risk of tobacco-related lung cancer, or is the damage permanent?

If you've never been a smoker and you develop lung cancer, how did you get it? Is it genetics, environment, radon, luck of the draw?

Is there a difference between smoking-related lung cancer and non-smoking-related lung cancer?

Are certain types of lung cancer more treatable than others? What's the general survival rate?

Are there differences between men and women in terms of susceptibility? Are there high-risk age groups?

("What You Need to Know on Smoking and Lung Cancer", Time, Aug.10)