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Lung cancer affects more than 200,000 Americans each year. Although cigarette smoking is the main cause, anyone can develop lung cancer. Lung cancer is always treatable, no matter the size, location, or whether the cancer has spread.
When a person inhales, the lungs absorb oxygen from the air and bring the oxygen into the bloodstream for delivery to the rest of the body. As the body's cells use oxygen, they release carbon dioxide. The bloodstream carries carbon dioxide back to the lungs, and the carbon dioxide leaves the body when a person exhales. The lungs contain many different types of cells. Most cells in the lung are epithelial cells. Epithelial cells line the airways and produce mucus, which lubricates and protects the lung. The lung also contains nerve cells, hormone-producing cells, blood cells, and structural or supporting cells.
There are two major types of lung cancer: non-small cell and small cell. Non-small cell lung cancer (NSCLC) comes from epithelial cells and is the most common type. Small cell lung cancer begins in the nerve cells or hormone-producing cells of the lung. The term “small cell” refers to the size and shape of the cancer cells as seen under a microscope. It is important for doctors to distinguish NSCLC from small cell lung cancer because the two types of cancer are usually treated in different ways.
Lung cancer begins when cells in the lung begin to change and grow uncontrollably and form a mass called a tumor (or, a lesion or nodule). A tumor can be benign (noncancerous) or malignant (cancerous). A cancerous tumor is a collection of a large number of cancer cells that have the ability to spread to other parts of the body. A lung tumor can begin anywhere in the lung.
Once a cancerous lung tumor begins to grow, it may or may not shed cancer cells. These cells can be carried away in blood or float away in the natural fluid, called lymph, which surrounds lung tissue. Lymph flows through tubes called lymphatic vessels that drain into collecting stations called lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes are located in the lungs, the center of the chest, and elsewhere in the body. The natural flow of lymph out of the lungs is toward the center of the chest, which explains why lung cancer often spreads there. When a cancer cell leaves its site of origin and moves into a lymph node or to a far away part of the body through the bloodstream, it is called metastasis.
The location and size of the initial lung tumor, and whether it has spread to lymph nodes or more distant sites, determines the stage of lung cancer. The type of lung cancer (NSCLC versus small cell) and stage of the disease (discussed later in Staging) determine what type of treatment is needed.
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In 2009, an estimated 219,440 adults (116,090 men and 103,350 women) in the United States will be diagnosed with lung cancer. Lung cancer is the second most common cancer and the leading cause of cancer deaths for men and women. It is estimated that 159,390 deaths (88,900 men and 70,490 women) from this disease will occur this year. For all people with lung cancer, the one-year survival rate (percentage of people who survive at least one year after the cancer is detected excluding those who die from other diseases) is 41%. The five-year relative survival rate is 15%.
Lung cancer represents 15% of all cancer diagnoses and 28% of all cancer deaths. For men, death rates have declined consistently since 1994 at a rate of nearly 2% each year. The death rates for women with lung cancer have stabilized since 2003 after increasing for several decades. For unclear reasons, black men have the highest incidence and the lowest survival rates of lung cancer.
These statistics should not be taken as a death sentence. It is important to remember that statistics do not apply to an individual person. No doctor can tell a person how long he or she will live with lung cancer. Some people who are told that their lung cancer can be cured do not live as long as patients who are told that their lung cancer is not curable. The important thing to remember is that lung cancer is treatable at any stage and that these treatments have been proven to help people live longer and better, despite a diagnosis of lung cancer.
Furthermore, these estimates are based on data from thousands of cases of this type of cancer in the United States each year, but the actual risk for a particular individual may differ. Because survival statistics are often measured in multi-year intervals, they may not represent advances made in the treatment or diagnosis of this cancer.
Statistics adapted from the American Cancer Society's publication, Cancer Facts & Figures 2009.
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