I'm afraid that I agree with Dr. G. By the way, Dr. G. is our "local" medical examiner, with an office quite close to MDAnderson on the campus of Orlando Regional Hospital.
Not all cancer is "caused" by smoking. I think we'd all agree to that. Some cancer is related to a long history of smoking. But, smoking is also related to a lot of other bad health problems - emphysema (which people can die from), a variety of heart problems, stroke. So, all in all, if you add those other diseases to the lung cancer deaths related to smoking, it's probaby the number one cause of death.
It's still important to make the point that not all lung cancer is smoking related, tho. I'm guessing that doctors who treat forever or long-term non-smokers don't think first of lung cancer when respiratory problems are present. If they did, they'd catch more cancers in earlier stages.
It will be interesting to see how many people I've offended. Hope not too many, as that wasn't the intent of this post.
Muriel