Lung Cancer
Lung cancer information such as how many people get lung cancer, what is lung cancer, risk factors of lung cancer and screening recommendations.
Lung cancer is the leading cause of cancer death in the United States for both men and women. More people die of lung cancer than colon, breast and prostate cancers combined. In 2006 there will be approximately 147,470 (92,700 men/81,770 women) new cases of lung cancers and about 162,460 people (90,330 men/72,130 women) will die of lung cancer in the United States. The lungs are two sponge-like organs found in the chest. They bring air in and out of the body by 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. Less often they can begin in other areas such as the trachea, bronchioles, or alveoli.
Lung cancer often takes many years to develop. First, there may be areas of pre-cancerous changes in the lung. These changes are not a mass or tumor. They can't be seen on an x-ray and they do not cause symptoms. But these changes can be found by special testing of cells in the lining of the airways of lungs damaged by smoke. As these pre-cancerous areas progress to become true cancer, they may make chemicals that cause new blood vessels to form nearby. These new blood vessels nourish the cancer cells and allow a tumor to form. Finally, the tumor becomes large enough to be seen on an x-ray. Once the lung cancer occurs, cancer cells can break away and spread to other parts of the body in a process called metastasis. Lung cancer is a life-threatening disease because it often spreads in this way before it is found.
Types of Lung Cancer
Approximately 15% of all lung cancers are small cell lung cancer. It often develops in the bronchi near the center of the chest. The cancer cells are small, but can multiply quickly and form large tumors that can spread throughout the body.
Non-small cell lung cancer (NSCLC)
Approximately 85% of all lung cancers are non-small cell types. There are three sub-types and differ in size, shape and chemical make-up. The squamous cell carcinomas (25% - 30%) tend to be found near the bronchus. The adenocarcinoma (40%) are usually found in the outer part of the lung and the large-cell undifferentiated carcinoma (10%-15%) can start in any part of the lung and tends to grow and spread quickly.
Lung Cancer Risk Factors
Lung Cancer Risk Factors:
- Smoking (8 out of 10 cases of lung cancer are due to tobacco smoke)
- Secondhand Smoke (non-smoking spouses of smokers have a 30% greater risk than spouses of nonsmokers)
- Asbestos
- Radon
- Arsenic
- Cancer-causing agents in the workplace (uranium, vinyl chloride, nickel chromates, coal products, mustard gas, chloromethyl ethers, gasoline, and diesel exhaust)
- Marijuana
- Other Diseases (silicosis and berylliosis)
- Personal and Family History
- Diet (low in fruits and vegetables)
- Air Pollution
- Radiation treatment to chest area
Lung Cancer Screening Recommendations
Most people with early lung cancer do not have symptoms so very few lung cancers are found at an early stage. When lung cancer is found early it is generally a result of a chest x-ray, CT scan or other test being completed for another reason. Ideally, a person's doctor should order testing for certain people based on the benefits and risks of procedures and treatments. The use of chest x-rays and checking sputum (spit) under a microscope to look for cancer cells has been studied for several years. These studies have shown that this kind of screening does not find many lung cancers early enough to improve a person's chance for a cure. For this reason, lung cancer screening is not suggested for all people, or even for people who smoke. Recently, though, a new x-ray method called spiral CT scanning has shown some promise in finding early lung cancer in smokers and former smokers. But it has not yet known if this test will lower the chances of dying from lung cancer.
To find out the answer to that question, a large study is going on. It is called the National Lung Screening Trial (NLST). For more information about the NLST, please contact the American Cancer Society or the National Cancer Institute. Although most lung cancers do not cause symptoms until they have spread you should report any of the following symptoms to your doctor right away. Symptoms include a cough that does not go away, chest pain (often made worse by deep breathing), hoarseness, weight loss/loss of appetite, bloody or rust-colored sputum, shortness of breath, recurring infections such as bronchitis or pneumonia and wheezing. Often these problems are caused by something other than cancer, but if it is cancer prompt treatment could extend your life and relieve symptoms.
Information gathered 10-21-04. Revised statistics and information on 11-3-06.