Lung Cancer

Lung cancer is the leading cancer killer in both men and women. There were an estimated 164,100 new cases of lung cancer and an estimated 156,900 deaths from lung cncer in the United States in 2000.

The rate of lung cancer cases appears to be dropping among white and African-American men in the United States, while it continues to rise among both white and African-American women.

There are two major types of lung cancer: non-small cell lung cancer and small cell lung cancer. Non-small cell lung cancer is much more common. It usually spreads to different parts of the body more slowly than small cell lung cancer. Squamous cell carcinoma, ademocarcinoma, and large cell carcinoma are three types of non-small cell lung cancer. Small cell lung cancer also called oat cell cancer, accounts for about 20% of all lung cancer.

Smoking is the number one cause of lung cancer. Lung cancer may also be the most tragic cancer because in most cases, it might have been prevented -- 87% of lung cancer cases are caused by smoking. Cigarette smoke contains more than 4,000 different chemicals, many of which are proven cancer-causing substances, or carcinogens. Smoking cigars or pipes also increases the risk of lung cancer.

Many of the chemicals in tobacco smoke also affect the the nonsmoker inhaling the smoke, making "secondhand smoking" another important cause of lung cancer. It is responsible for approximately 3,000 lung cancer deaths and as many as 62,000 deaths from heart disease annually.

Radon is considered to be the second leading cause of lung cancer in the U.S. today. Radon gas can come up through the soil under a home or building and enter through gaps and cracks in the foundation or insulation, as well as through pipes, drains, walls or other openings. Radon causes between 15,000 and 22,000 lung cancer deaths each year in the United States -- 12 percent of all lung cancer deaths are linked to radon.

Because you cannot see or smell radon, the only way to tell if you are being exposed to the gas is by measuring radon levels. Exposure to radon in combination with cigarette smoking, greatly increases the risk of lung cancer. That means for smokers, exposure to radon is an even greater health risk.

Another leading cause of lung cancer is on-the-job exposure to cancer-causing substances or carcinogens. Asbestos is a well-known, work-related substance that can cause lung cancer, but there are many others, including uranium, arsenic, and certain petroleum products.

Lung cancer takes many years to develop. But changes in the lung can begin almost as soon as a person is exposed to cancer-causing substances. Soon after exposure begins, a few abnormal cells may appear in the lining of the bronchi (the main breathing tubes). If a person continues to be exposed to the cancer-causing substance, more abnormal cells will appear. These cells may be on their way to becoming cancerous and forming a tumor.

In its early stages, lung cancer usually does not cause symptoms. When symptoms