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. In 2009, 219,440 new cases of lung cancer are 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:
Non-small cell lung cancer 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.
Small cell lung cancer, sometimes called oat cell cancer because 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.
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.
How is lung cancer diagnosed?
In addition to a complete medical history to check for risk factors and symptoms, and a physical examination to provide other information about signs of lung cancer and other health problems, procedures used to diagnose lung cancer may include:
- chest x-ray – to look for any mass or spot on the lungs.
- other special x-rays – a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film; can provide more precise information about the size, shape, and position of a tumor.
- computed tomography scan (Also called a CT or CAT scan.) – a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- sputum cytology – a study of phlegm (mucus) cells under a microscope.
- needle biopsy – a needle is guided into the mass while the lungs are being viewed on a CT scan and a sample of the mass is removed and evaluated in the pathology laboratory under a microscope.
- bronchoscopy – the examination of the bronchi (the main airways of the lungs) using a flexible tube (bronchoscope) passed down the mouth or nose. Bronchoscopy helps to evaluate and diagnose lung problems, assess blockages, obtain samples of tissue and/or fluid, and/or to help remove a foreign body.
- mediastinoscopy – a process in which a small cut is made in the neck so that a tissue sample can be taken from the lymph nodes (mediastinal nodes) along the windpipe and the major bronchial tube areas to evaluate under a microscope.
- x-rays and scans of the brain, liver, bone, and adrenal glands – to determine if the cancer has spread from where it started into other areas of the body.
- Other tests and procedures may be used as well.
Treatment for lung cancer:
Specific treatment for lung cancer will be determined by your physician based on:
- your age, overall health, and medical history
- extent of the disease
- your tolerance for specific medications, procedures, or therapies
- expectations for the course of the disease
- your opinion or preference