Risk factors According to the Nurses' Health Study, the risk of pulmonary<unk>  increases substantially after a long duration of tobacco smoking: smokers with a previous smoking duration of 30–40 years are more than twice as likely to develop lung<unk>  compared to never-smokers (relative risk of approximately 2.4); a duration of more than 40 years increases relative risk to 5. This cancer usually is seen peripherally in the lungs, as opposed to small cell lung cancer and squamous cell lung cancer, which both tend to be more centrally located, although it may also occur as central lesions. For unknown reasons, it often arises in relation to peripheral lung scars. The current theory is that the scar probably occurred secondary to the tumor, rather than causing the tumor. The<unk>  has an increased incidence in smokers, and is the most common type of lung cancer seen in non-smokers and women. Deeper inhalation of cigarette smoke results in peripheral lesions that are often the case in<unk> . Generally,<unk>  grows more slowly and forms smaller masses than the other subtypes. However, it tends to metastasize at an early stage.
Adenocarcinoma of the lung
Giant-cell carcinoma of the lung
Sarcomatoid carcinoma of the lung
Acinic cell carcinoma of the lung
Squamous-cell carcinoma of the lung
Non-small-cell lung carcinoma
Pulmonary sclerosing pneumocytoma
Epithelial-myoepithelial carcinoma of the lung