In the United States, more people (161,840 per year) die of lung cancers than of prostate cancer, breast cancer and colon cancer combined. Presently, there are over 43 million current smokers and over 47 million ex-smokers living in the US. Due to the lag time between smoking and the development of cancer, there are significant numbers of ex-smokers and current smokers who may develop lung cancer compared to never smokers.