These conditions are all separate topics, with their treatment following that the the areas where they more commonly arise. Cancers from other areas may spread to the lungs, especially adenocarcinomas and sarcomas from other organs. The lungs are rich in blood and are a fertile area for other cancers to spread to. These are dealt with when considering the treatment for metastasis of these particular cancers. Each year there are about 170,000 new cases of lung cancer in the U.S.A. and 150,000 deaths attributable to this disease.
Lung cancer is the most frequent fatal cancer, for both men and women, in the United States.
Worldwide, there are 1 million new cases per year. Over the past 5 decades the number of yearly cases has been increasing, and the worldwide incidence may double to 2 million per year in the coming decade. Like any cancer, the exact reason why one particular person gets lung cancer and another does not remains unknown. The risk goes up with the number of cigarettes smoked. It takes 5 years after quitting smoking for the risk to appreciably decrease, and at 15 years after the risk approaches the never-smoked level.