Lung Cancer Research Paper

Lung cancer: The beginning, progression, and how it exerts its lethal effects

Lung cancer is the second most common cancer in both men and women, but is the leading cause of cancer death in the United States.

All cells in the body contain the genetic material called deoxyribonucleic acid (DNA). Every time a mature cell divides into two new cells, its DNA is exactly duplicated. The cells are copies of the original cell, identical in every way. In this way our bodies continually replenish themselves. Old cells die off and the next generation replaces them. A cancer begins with an error, or mutation, in a cell’s DNA. DNA mutations can be caused by the normal aging process or through environmental factors. (http://www.lungcancer.org) The risk of developing lung cancer is highest in smokers, but many people who do not smoke also develop lung cancer each year. High levels of pollution, radiation and asbestos exposure may also

increase risk.
There are three forms of lung cancer, the most common of which is squamous- cell carcinoma.

In its early stage, basal cells of bronchial epithelium multiply and the ciliated pseudostratified epithelium transform into the stratified aquamous type. As the dividing epithelial cell invades the underlying tissues of the brochial wall, the bronchus develops bleeding lesions. Dense swirled masses of keratin appear in the lung parenchyma and replace functional respiratory tissue (Saladin, pg 883)

Adenocarcinoma is a second form of lung cancer; it is originated in the mucous gland of the lamina propria. This form of lung cancer occurs more often in women, and most often in the peripheral lung fields. It is slow growing but often is not diagnosed until metastasis has occurred.

Small –cell (sometime called oat cell carcinoma) is the least common (10% - 20% of malignancies) but is the most dangerous form because the small –cell grows rapidly and often has metastasized by the time of diagnosis. Small cell lung cancer occurs almost exclusively in heavy

smokers.
The mucous membranes of the large bronchis is where is originated over 90% of the lung tumors As a tumor invades the bronchial wall and grows around it, it compresses the airway and may cause atelectasis (collapse) of more distal part of the lung. Lung cancer metastasizes so rapidly that it has usually spread to other organs by the time it is diagnosed. Common sites of lung cancer metastasis include the brain, bones, pericardium, heart, opposite lung, liver, adrenal gland and lymph nodes
Once the lung cancer has been diagnosed, the doctor will work to determine the extent (stage) of the cancer. The cancer's stage helps to decide what treatment is most appropriate.

Stages of lung cancer
• Stage I. Cancer is limited to the lung and hasn't spread to the lymph nodes. The tumor is generally smaller than 2 inches (5 centimeters) across.
• Stage II. The tumor at this stage may have grown larger than 2 inches, or it may be a smaller tumor that involves nearby structures, such as the chest wall, the diaphragm or the lining around the lungs (pleura). Cancer may also have spread to the nearby lymph nodes.
• Stage III. The tumor at this stage may have grown very large and invaded other organs near the lungs. Or this stage may indicate a smaller tumor accompanied by cancer cells in lymph nodes farther away from the lungs.
• Stage IV. Cancer has spread beyond the affected lung to the other lung or to distant areas of the body.

. Only 7% of patients surviving for 5 years this means that the recoverability is low.