Adenocarcinomas are often found in an outer area of the lung.
Squamous cell carcinomas are usually found in the center of the
lung next to an air tube (bronchus). Large cell carcinomas can
occur in any part of the lung. They tend to grow and spread
faster than the other two types. Causes, incidence, and risk
factors Smoking causes most cases of lung cancer. The risk
depends on the number of cigarettes you smoke every day and for
how long you have smoked. Being around the smoke from other
people (secondhand smoke) also raises your risk for lung cancer.
However, some people who do not smoke and have never smoked
develop lung cancer. Research shows that smoking marijuana may
help cancer cells grow, but there is no direct link between the
drug and developing lung cancer. High levels of air pollution
and drinking water containing high levels of arsenic can
increase your risk for lung cancer. A history of radiation
therapy to the lungs can also increase the risk. Working with or
near the following cancer-causing ch