The diagnosis of lung cancer brings with it many questions and a need for clear, understandable answers. We hope this National Cancer Institute (NCI) booklet (NIH Publication No. 99-1553) will help. It provides information about some causes and ways to prevent lung cancer, and it describes the symptoms, detection, diagnosis, and treatment of this disease. Having this important information can make it easier for patients and their families to handle the challenges they face.
Cancer research has led to progress against lung cancer -- and our knowledge is increasing. Researchers continue to look for better ways to prevent, detect, diagnose, and treat lung cancer. The Cancer Information Service and the other NCI resources listed under "National Cancer Institute Information Resources" can provide the latest, most accurate information on lung cancer. Publications mentioned in this book and others are available from the Cancer Information Service at 1-800-4-CANCER. Many NCI publications are also available on the Internet at the Web sites listed in the "National Cancer Institute Information Resources" section at the end of this booklet.
Understanding the Cancer Process
All types of cancer develop in our cells, the body's basic unit of life. To understand cancer, it is helpful to know how normal cells become cancerous.
The body is made up of many types of cells. Normally, cells grow, divide, and produce more cells as needed to keep the body healthy and functioning properly. Sometimes, however, the process goes astray -- cells keep dividing when new cells are not needed. The mass of extra cells forms a growth or tumor. Tumors can be benign or malignant.
Benign tumors are not cancer. They often can be removed and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely a threat to life.
Malignant tumors are cancer. Cells in malignant tumors are abnormal and divide without control or order. These cancer cells can invade and destroy the tissue around them. Cancer cells can also
break away from a malignant tumor and enter the bloodstream or lymphatic system (the tissues and organs that produce, store, and carry white blood cells that fight infection and other diseases). This process, called metastasis, is how cancer spreads from the original (primary) tumor to form new (secondary) tumors in
other parts of the body.
The Lungs
The lungs, a pair of sponge-like, cone-shaped organs, are part of the respiratory system. The right lung has three sections, called lobes; it is a little larger than the left lung, which has two lobes. When we breathe in, the lungs take in oxygen, which our cells need to live and carry out their normal functions. When
we breathe out, the lungs get rid of carbon dioxide, which is a waste product of the body's cells.
Understanding Lung Cancer
Cancers that begin in the lungs are divided into two major types, non-small cell lung cancer and small cell lung cancer, depending on how the cells look under a microscope. Each type of lung cancer grows and spreads in different ways and is treated differently.
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Nonsmall cell lung cancer is more common than small cell lung cancer, and it generally grows and spreads more slowly. There are three main types of non-small cell lung cancer. They are named for the type of cells in which the cancer develops: squamous cell carcinoma (also called epidermoid carcinoma), adenocarcinoma, and large cell carcinoma.
Small cell lung cancer, sometimes called oatcell cancer, is less common than non-small cell lung cancer. This type of lung cancer grows more quickly and is more likely to spread to other organs in the body.
| Cancers that begin in the lungs are divided into two major types, non-small cell lung cancer and small cell lung cancer, depending on how the cells look under a microscope. Each type of lung cancer grows and spreads in different ways and is treated differently. |
Lung Cancer: Who's at Risk?
Researchers have discovered several causes of lung cancer -- most are related
to the use of tobacco.
- Cigarettes. Smoking cigarettes causes lung cancer. Harmful substances,
called carcinogens, in tobacco damage the
cells in the lungs. Over time, the damaged cells may become cancerous. The
likelihood that a smoker will develop lung cancer is affected by the age at
which smoking began, how long the person has smoked, the number of cigarettes
smoked per day, and how deeply the smoker inhales. Stopping smoking greatly
reduces a person's risk for developing lung cancer. - Cigars and Pipes. Cigar and pipe smokers have a higher risk of lung
cancer than nonsmokers. The number of years a person smokes, the number of pipes
or cigars smoked per day, and how deeply the person inhales all affect the risk
of developing lung cancer. Even cigar and pipe smokers who do not inhale are at
increased risk for lung, mouth, and other types of cancer. - Environmental Tobacco Smoke. The chance of developing lung cancer is
increased by exposure to environmental tobacco smoke (ETS) -- the smoke in the
air when someone else smok
