Pulmonary
- Critical Care Associates
of East Texas
Jeffrey M.
Shea, M.D., F.C.C.P.
Venkatesh Donty, M.D.
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Jeffrey M.
Shea, M.D., F.C.C.P. |
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Introduction Lung Cancer is the most common cancer-related cause of death among men and women. It is the second most commonly occurring cancer among men and the third most commonly occurring cancer among women. The rate of lung cancer cases is on the rise among women. There were more than 177,000 new cases of lung cancer in the U.S. in 1996 alone. The rate of lung cancer cases appears to be declining among white men in the U.S., while it continues to increase among African-American men and among both white and African-American women. An estimated 158,700 Americans died to lung cancer in 1996. Lung cancer is usually rare in people under the age of 40. The number of cases goes up after the age of 50 and even more so often after the age of 65. What is Cancer? Cancer is a group of diseases. All forms of cancer cause cells in the body to change and grow out of control. Cancer cells form a lump or mass called a tumor. Cells from this tumor can break away and travel to other parts of the body and they continue to grow. This process is called metastasis. Blood cancers such as leukemia do not form tumors. All tumors are not cancerous. A tumor that is not cancer is called benign. These tumors do not grow and spread the way cancer does nor are they usually a threat to life. A cancerous tumor is called malignant. What is Lung Cancer? Cancers are named for the part of the body where the cancer starts. Lung cancer starts in the lungs. You have a right and left lung. The right lung has three sections; the left has two sections. These are called lobes. The left lung is smaller because the heart takes up more room on that side of the body. The lungs bring air in and out, bringing in oxygen and expelling carbon dioxide gas, a waste product of the body. The pleura are the lining that surrounds the lungs and helps protect the lungs. The windpipe (trachea) brings the air down into the lungs. It divides into tubes called bronchi, then divides into smaller branches called bronchioles. On the end of these small branches are tiny air sacs called the alveoli. Most of the lung cancers start in the lining of the bronchi. Lung cancer can also begin in other areas like the trachea, bronchioles, or alveoli. Lung cancer may also be the most tragic cancer because, in most cases, it might have been prevented. How does Lung Cancer develop? Lung cancer takes many years to develop. However, changes in the lung can begin almost immediately upon exposure to carcinogens (cancer-causing substances). Soon after exposure begins, microscopic examination of the tissue lining the bronchi (the main breathing tubes) will reveal a few unusual cells. With continued exposure, more abnormal cells appear. These cells may mutate on their way to becoming cancerous and forming a tumor. The symptoms of the cancer vary depending on several factors, including where in the lung the tumor is found. If the cancer is located in one of the bronchi, it can irritate the lining of the bronchus (one of the main airways that branches off of the trachea or windpipe) and cause a chronic cough. The cancerous area may bleed when a person coughs. If the tumor grows larger, it may fill the bronchus so that air can’t pass in or out. A blocked bronchus may also cause repeated lung infections or pneumonia. A tumor located in the outer part of the lung may not produce any symptoms until it is fairly large. Sometimes the first sign may be chest pain from the tumor growing into the lining of the lungs or the ribs and muscle of the chest wall. A person’s lungs have an extensive networks of blood and lymph vessels. Cancer cells may grow into these vessels and be carried by the blood or lymph to circulate through the body. The cancer cells may then be deposited in other organs of the body. The first site of tumor metastasis is usually the lymph nodes within the lungs and the mediastinum (the space between the two lungs in the middle of the chest). What causes Lung Cancer? Smoking is the number one cause of lung cancer. Up to 90% of the lung cancers are caused smoking tobacco. Cigarette smoke contains more than 4,000 different chemicals, many of which are proven carcinogens, while hundreds of others increase the cancer-causing power of carcinogens. Many of these chemicals also affect the nonsmoker inhaling "secondhand" or "sidestream" smoke, making "passive smoking" another important cause of lung cancer. The U.S. Environmental Protection Agency (EPA) reported in 1993 that involuntary smoking causes 3,000 lung cancer deaths in nonsmokers each year. Sidestream smoke, with its high concentration of carcinogens, goes directly into the air from burning tobacco (cigarettes, cigars, etc.) and is inhaled by both smokers and nonsmokers. If you smoke, you are much more likely to develop the disease; men who smoke are estimated to be 22 times more likely to develop lung cancer, while women who smoke are estimated to be 12 times more likely. The more you smoke and the longer you smoke the greater your risk of lung cancer. But if you stop smoking, the risk of cancer decreases steadily each year as normal cells replace abnormal cells. In ten years, the risk decreases to a level that is 30 to 50 percent of the risk for people who continue to smoke. In addition, quitting smoking dramatically reduces the risk of developing other smoking-related diseases, such as heart disease and stroke, and significantly reduces the risk of serious emphysema and bronchitis. Radon, by its own action and by its interaction with cigarette smoking, is considered to be the second leading cause of lung cancer in the U.S. today. Radon is a radioactive gas that is found in the earth and is formed by the natural breakdown of radium, which is a radioactive product of decaying uranium. Radon problems have been identified in every state. The EPA estimates that nearly 1 out of every 15 homes in the U.S. has indoor radon levels at or above the EPA’s recommended action guideline level of four picocuries per liter of air (pCi/L) on a yearly average. Radon can be a problem in schools and workplaces, too. Because radon is invisible and odorless, the only way to determine if you are being exposed to the gas is by measuring radon levels. In addition, exposure to radon, in combination with cigarette smoking, significantly increases the risk of lung cancer. Therefore, for smokers, exposure to radon is an even greater health risk. Another leading cause of lung cancer is on-the-job exposure to carcinogens. Asbestos is perhaps the best known of the industrial substances associated with lung cancer, but there are many cancer-causing substances that people may deal with at work. These include asbestos, uranium, arsenic, certain petroleum products, and others. In addition, it is important to realize that there are many different jobs that may involve exposure. Some examples are working with certain types of insulation, working in certain environments, such as with coke ovens and repairing brakes. As is the case with radon, when exposure to job-related carcinogens is combined with smoking, the risk of getting lung cancer is sharply increased. How is Lung Cancer detected? In its early stages and even later, lung cancer is usually silent. When symptoms occur, the cancer is often advanced. Symptoms of lung cancer include:
These conditions are also symptomatic of many other lung problems; thus, when they occur, they warrant medical investigation. When a person goes for an examination, his or her doctor will take an extensive medical history, noting any possible hazardous exposure. This is followed by a thorough physical examination. If the patient has a productive cough (a cough that produces sputum), the sputum may be examined for cancer cells. The doctor may order a chest X-ray or specialized X-ray such as a CAT scan, which help to locate any abnormal spots in the lungs. The doctor may do a bronchoscopy to look inside the bronchial tubes and lungs. A bronchoscope is a small tube inserted through the nose or mouth, down the throat, into the bronchial tubes. During this procedure the doctor may also obtain a biopsy or other sample of lung tissue and cells which are viewed under a microscope to determine if they are cancerous and if so, to identify the type of cancer involved. Biopsies of lung tissue or of the lymph nodes between the lungs may be performed using other techniques as well. Types of Lung Cancer There are two major types of lung cancer: small cell lung cancer and non-small cell lung cancer. Small cell lung cancer accounts for about one fourth of all lung cancers. It is also called oat cell lung cancer. Although the cancer cells are small, they can multiply quickly and form large tumors. The tumors can spread to the lymph nodes and to other organs such as the brain, the liver, and the bones. Smoking usually causes small cell lung cancer. Non-small cell lung cancer is the most common type of lung cancer. There are three subtypes within this group. Some types grow more quickly than others do. Staging Lung Cancer Staging is the process of finding out how far the cancer has spread. This is very important because treatment and prognosis for recovery depend on the stage of the cancer. There are different staging systems for small cell and non-small cell lung cancer. For small cell lung cancer a two-stage system is most often used. These are limited stage and extensive stage. Limited stage usually means that the cancer is only in one lung and in lymph nodes on the same side of the chest. If the cancer has spread to the other lung, to lymph nodes on the other side of the chest, or to distant organs, it is called extensive. Many people with small cell lung cancer will already have extensive disease when it is found. The staging system for non-small cell lung cancer is more detailed. It is usually written as a Roman numeral from 0 to IV. The smaller the number, the less the cancer has spread. A higher number, for example stage IV, means a more serious stage of the disease. Treatment Progress has been made in treating lung cancer with surgery, radiation, and chemotherapy. Surgery has been improved, and more is known about the best way to combine drugs to treat different types of cancer. The best treatment depends on the type of cancer, the stage of the cancer, and your overall health. Sometimes there is a combination of two or three treatments used. Surgery Surgery is used more often for non-small cell lung cancer. For early stage non-small cell lung cancer, surgery may cure lung cancer. The surgeon may remove a part of the lung or the entire lung. Small cell lung cancer has usually spread too far by the time it is found for surgery to be effective. Chemotherapy Chemotherapy is the use of anti-cancer drugs to kill cancer cells. This can be given by pills or shots. When chemotherapy is used, it enters the bloodstream and reaches all areas of the body. It is useful for cancer that has spread to other organs of the body. Several drugs may be given at the same time. Chemotherapy may have some side effects. The side effects will depend on the type of drug, how much is prescribed, and how long the treatment course is. Most of the side effects will go away when the treatment is over. Chemotherapy may be used:
Radiation Radiation is the use of high-energy x-rays to kill or shrink cancer cells. This is sometimes used as the main treatment of lung cancer in patients who may not be healthy enough to have surgery. Radiation may be used after surgery to kill small areas of cancer that can’t be seen and removed during surgery. Radiation can also be used to relieve symptoms such as pain, bleeding, and trouble swallowing. There can be side effects from radiation. Most of these will go away after the course of treatment is over. The skin in the area treated may look sunburned and then tan. The skin usually returns to normal within 6-12 months. Side effects may also include feeling tired and some patients experience nausea. Summary If you are a smoker, STOP SMOKING. If you are a non-smoker, make sure that your rights to a smoke-free environment are upheld. Strive for a smoke-free environment both at home and at work. Test your home for radon if you live in an area known to have high levels. Ask question about your work environment if you are exposed to industrial dusts and fumes. Lung cancer is the leading cancer killer in the United States and until there is a cure, the only way to defeat lung cancer is to prevent it from ever happening.
Additional Information You can find us on the internet at www.pcca.net for other pulmonary topics and patient
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