MSG,
I don't want to come across as in anyway defending smoking, but I don't believe your assumption that 20% of smokers develop lung cancer is anywhere near accurate.

Research shows that even among long-term, heavy smokers, the risk of getting lung cancer can vary dramatically -- from less than 1 percent to 15 percent.

To be in Sloan-Kettering's long-term, heavy smokers, high risk category, the person has to have smoked at least a pack a day for the last 20 years and be over 50 years old.

SOURCES: Peter Bach, M.D., epidemiologist and pulmonary physician, Memorial Sloan-Kettering Cancer Center, New York

http://www.lifeclinic.com/fullpage.aspx?prid=512291&type=1

Don
TXN2bM0 Stage IVa SCC-Occult Primary
FNA 6/6/08-SCC in node<2cm
PET/CT 6/19/08-SCC in 2nd node<1cm
HiRes CT 6/21/08
Exploratory,Tonsillectomy(benign),Right SND 6/23/08
PEG 7/3/08-11/6/08
35 TomoTherapy 7/16/08-9/04/08 No Chemo
Clear PET/CT 11/15/08, 5/15/09, 5/28/10, 7/8/11