Lung Cancer


Lung cancer is not just one disease but rather a group of diseases. All forms of cancer
cause cells in the body to change and grow out of control. Most types of cancer cells form
a lump or mass called a tumor. Cells from the tumor can break away and travel to other
parts of the body where they can continue to grow. This spreading process is called
metastasis. When cancer spreads, it is still named after the part of the body where it
started. For example, if breast cancer spreads to the lungs, it is still breast cancer, not lung
cancer. Another word for cancerous is malignant, so a cancerous tumor is referred to as
malignant. But not all tumors are cancer. A tumor that is not cancer is called benign.
Benign tumors do not grow and spread the way cancer does. They are usually not a threat
to life. A few cancers, such as blood cancers (leukemia), do not form a tumor. Most
cancers are named after the part of the body where the cancer first starts. Lung cancer
begins in the lungs. The lungs are two sponge-like organs in the chest. The right lung has
three sections, called lobes. The left lung has two lobes. It is smaller because the heart
takes up more room on that side of the body. The lungs bring air in and out of the body,
taking in oxygen and getting rid of carbon dioxide gas, a waste product. The lining around
the lungs, called the pleura, helps to protect the lungs and allows them to move during
breathing. The windpipe (trachea) brings air down into the lungs. It divides into tubes
called bronchi, which divide into smaller branches called bronchioles. At the end of these
small branches are tiny air sacs known as alveoli. Most lung cancers start in the lining of
the bronchi but they can also begin in other areas such as the trachea, bronchioles, or
alveoli. Lung cancer often takes many years to develop. Once the lung cancer occurs,
cancer cells can break away and spread to other parts of the body. Lung cancer is a life-
threatening disease because it often spreads in this way before it is found. Lung cancer is
the leading cause of cancer death for both men and women. During the year 2000 there
will be about 164,100 new cases of lung cancer in this country. About 156,900 people will
die of lung cancer: about 89,300 men and 67,600 women. More people die of lung cancer
than of colon, breast, and prostate cancers combined. Lung cancer is fairly rare in people
under the age of 40. The average age of people found to have lung cancer is 60. If lung
cancer is found and treated by surgery early, before it has spread to lymph nodes or other
organs, the five-year survival rate is about 42%. However, few lung cancers are found at
this early stage. The five-year survival rate for all stages of lung cancer combined was
14% in 1995, the last year for which we have national data. A risk factor is something that
increases a person\'s chance of getting a disease. Some risk factors, like smoking, can be
controlled. Others, such as a person\'s age, can\'t be changed. Smoking is by far the leading
risk factor for lung cancer. More than 8 out of 10 lung cancers are thought to result from
smoking. The longer a person has been smoking, and the more packs per day smoked, the
greater the risk. If a person stops smoking before lung cancer develops, the lung tissue
slowly returns to normal. Stopping smoking at any age lowers the risk of lung cancer.
Cigar and pipe smoking are almost as likely to cause lung cancer as cigarette smoking.
There is no evidence that smoking low tar cigarettes reduces the risk of lung cancer.
Nonsmokers who breathe the smoke of others also increase their risk of lung cancer. Non-
smoking spouses of smokers, for example, have a 30% greater risk of developing lung
cancer than do spouses of nonsmokers. Workers exposed to tobacco smoke in the
workplace are also more likely to get lung cancer. There are other risk factors for lung
cancer besides smoking. People who work with asbestos have a higher risk of getting lung
cancer. If they also smoke, the risk is greatly increased. The type of lung cancer linked to
asbestos, mesothelioma, often starts in the pleura. This type of cancer is covered in a
separate American Cancer Society document. Although