Almost all cases of this type of lung cancer are a result of smoking. They are only vary rarely diagnosed in someone who has never smoked.
"If we see it in a non-smoker, we ask 'are you sure?' and recheck the pathology reports," Gregory Kalemberian, MD, clinical professor of medicine in hematology/oncology at The University of Michigan in Ann Arbor. The more "pack years" you smoke (defined as the number of packs smoked per day per year), the greater the risk of small cell, added Dr. Rohs.
Guys, for any of you out there, if you smoke, please please stop now. Its an incredibly selfish thing do to, both to yourself, and to those who love and care about you (not to mention those who need to help cover your medical costs).
I might start a separate thread on this topic. If there is one person I can save with my comments on smoking, its worth it.