Lung Cancer Overview
What is lung cancer?
Lung cancer is cancer that usually starts in the lining of the bronchi (the main airways of the lungs), but can also begin in other areas of the respiratory system, including the trachea, bronchioles, or alveoli. It is the leading cause of cancer death in both men and women. For 2009, more than 219,440 new cases of lung cancer were expected, according to the American Cancer Society.
Lung cancers are believed to develop over a period of many years.
Nearly all lung cancers are carcinomas, a cancer that begins in the lining or covering tissues of an organ. The tumor cells of each type of lung cancer grow and spread differently, and each type requires different treatment. About 85 percent to 90 percent of lung cancers belong to the group called non-small cell lung cancer.
Lung cancers are generally divided into two types:
- Small cell lung cancer – sometimes called oat cell cancerbecause the cancer cells may look like oats when viewed under a microscope – grows rapidly and quickly spreads to other organs. There are two stages of small cell lung cancer:
- Limited – cancer is generally found only in one lung. There may also be cancer in nearby lymph nodes on the same side of the chest.
- Extensive – cancer has spread beyond the primary tumor in the lung into other parts of the body.
- Non-small cell lung cancer(NSCLC) is much more common than small cell lung cancer. The three main kinds of non-small cell lung cancer are named for the type of cells in the tumor:
- Squamous cell carcinoma is also called epidermoid carcinoma. It often begins in the bronchi and usually does not spread as quickly as other types of lung cancer.
- Adenocarcinoma usually begins along the outer edges of the lungs and under the lining of the bronchi. It is the most common type of lung cancer in people who have never smoked.
- Large cell carcinomas are a group of cancers with large, abnormal-looking cells. These tumors may begin anywhere in the lungs.
It is important to find out what kind of lung cancer a person has. The different types of carcinomas, involving different regions of the lung, may cause different symptoms and are treated differently.