Introduction

Lung cancer is the second most common cancer of all cancers in both men and women in the United States after skin cancer. An estimated 222,520 adults will be diagnosed with the disease in 2010, according to the American Cancer Society.

Lung cancer starts when abnormal cells in the tissues of the lung, usually in the cells that line the air passages, begin to grow out of control. A lump of cancer cells (also called a malignant tumor, mass, nodule, or lesion) then forms.  There are two major types of lung cancer—non-small cell lung cancer (NSCLC) and small cell lung cancer. It is important that the type (non-small cell versus small cell) be determined because each type is usually treated differently.

Non-small cell lung cancer is more common than small cell lung cancer, and it generally grows and spreads more slowly.

Small cell lung cancer grows more quickly than non-small cell lung cancer and is more likely to spread to other organs in the body.

Other names for lung cancer include pulmonary carcinoma, bronchial carcinoma, and bronchoalveolar cell carcinoma. “Pulmonary” means “related to the lung” and comes from the Latin word for lung (pulmo). “Bronchoalveolar” describes the small lung structures that branch out from the bronchi (the main airways of the lungs).

The leading cause of lung cancer is smoking tobacco, which causes more than 90 percent of all lung cancers. However, not all people who smoke develop lung cancer, and not all cases of lung cancer are caused by smoking. Other risk factors for lung cancer include breathing secondary smoke (smoke from other people’s tobacco use), smoking marijuana, and exposure to asbestos or other harmful agents, such as radioactive substances, arsenic, vinyl, chloride, mustard gas, radon gas, or diesel exhaust.