SMALL CELL LUNG CANCER TREATMENT INFORMATION
The paired lungs develop from lung buds in the human embryo during a period of rapid cell division. The main type of cell in the lungs is called "epithelial", meaning a lining cell. Mucous is formed by "adeno" cells which fold into glands. Another type of cell, called the "type II" cell, secretes "surfactant" which provides the stiffness for lung tissue. All of these cells divide quickly during womb life, infancy and puberty, but growth slows dramatically by adulthood. In adults, the cells only divide to replace ones lost to injury or old age. Air breathed in passes though the throat into the larynx, where the vocal cords can form sounds. Below the larynx is the trachea, a tube ringed with cartilage which helps keep it from collapsing. The trachea splits ("bifurcates") in an upside-down "Y" with the arms of the "Y" going into each lung. The part of the trachea that actually enters each lung is called the "mainstem bronchus" ; there is a right and a left one to correspond with each lung. The area where the mainstem bronchi enter is called the "hilum" of each lung, the main blood vessels also enter at the hilum. The main bronchi branch out into smaller "lobar" and "segmental" bronchi to carry the air into the lungs. The right lung is made up of 3 lobes, and the left lung of 2 lobes. Each lobe is made up of smaller segments. The air breathed into the lungs ultimately gets to the tiny air sacs, called "alveoli", which provides the surface for the oxygen in air to mix with the blood. Also, the alveoli allow the carbon dioxide in the blood to be released into the lungs to get exhaled. The lungs are surrounded by an outer membrane called the "pleura" -- it is composed of 2 parts, an inner "visceral" pleura and an outer "parietal" pleura. There are bean-sized filters, called "lymph nodes" along the bronchi, which connect to each other via "lymph channels" . The lymph nodes contain lots of white blood cells and make up part of the immune system to help purify the blood. The lungs have a very rich blood supply, both from the blood they are oxygenating from the heart, which will be circulated to the rest of the body, and from the aorta, which provides nourishment for the lungs themselves. Thus, disease in the lungs, such as infection or cancer, can spread through the lymph channels and/or bloodstream to other areas of the body. When people smoke tobacco over many years, the lungs lose their softness and start to become stiff. Then the lungs are more prone to infection and inflammation of the bronchi, called "bronchitis", and produce soothing sputum. The air sacs are gradually destroyed, and stale air gets trapped in the lungs. This is called "emphysema" . It gradually destroys the interface between the air sacs and the bloodstream, compromising the ability of the lungs to oxygenate the blood and to release the built up carbon dioxide waste product. About 1 in 5 people with emphysema will eventually develop lung cancer. What is Lung Cancer? Normally, the division of cells in the adult lung to make new cells is under very tight control. This control is exerted by the "genes" inside each cell, which are housed in long clumps forming "chromosomes", which are visible under a light microscope. The genes themselves are made up of DNA, the master genetic code material. If the genes are damaged, say by chemicals or radiation, the control over cell division may be lost in one particular cell. Ultimately, cancer is considered a disease of the DNA. Lung cancer starts in a single lung cell . That cell starts dividing haphazardly, making millions and billions of copies of itself. It takes up the nourishment needed by other cells, depriving them so the cancer can continue to grow. Quickly growing cells can clump up to form a "tumor" . A tumor simply means a swelling, it can be caused by inflammation or infection. A "benign" tumor only grows in it's local area (although it may get quite large)-- it cannot spread and is not cancer. By contrast, a tumor which can spread to other body areas is called "malignant" and this is cancer . The process of cancer spread to other areas is called "metastasis", so only malignant tumors (i.e. cancer) can metastasize. Theoretically, cancer can spread to any area of the body, and it often grows better in it's area of spread than in it's area of origin ("primary site") . It is this capacity for spread that makes cancer so dangerous. If not treated successfully, it ultimately kills by debility, anemia, infection, compromise of other organs and interference with normal body functions. What are the Types of Lung Cancer? Depending on which type of cell in the lung goes awry, different types of lung cancer may arise. Although mixed types may occur, lung cancer is commonly broken down into 4 basic categories, and a smattering of much less common types. The most common type is Squamous Cell Carcinoma (35% of cases). It starts from the cells lining the bronchi, especially when they have been repeatedly damaged by smoke or other irritation. Normally, squamous cells are the type that line the mouth, anus, vagina and skin-- they are resistant to abrasion and heal quickly. Fascinatingly the normal "cuboidal" epithelium of the lung can start to turn into squamous cells with repeated irritation, a process called "dedifferentiation" . If this conversion is not totally successful, a cancerous squamous cell may arise. The second most common type of lung cancer is Adenocarcinoma (30% of cases) which arises from glands, and the cells lining the air sacs. It is usually found in the periphery of the lungs, as opposed to squamous cell which commonly has a more central location along the bronchioles (that is arises in the middle of the chest). This is the type common in non-smokers. The third most common type is Small Cell Carcinoma, also called "oat cell" (20% of cases). It seems to arise from "neuroendocrine" cells, which produce small amounts of local hormones. The specific cell that small cell lung cancer arises from appears to be the "Kulchitsky" cell, a neuroendocrine cell within the lining of the bronchioles. There are 3 subtypes of small cell cancer-- "Oat Cell", "Intermediate" and "Combined" (mixed type). Over 90% of cases are the Oat Cell type, and it is the type that best responds to chemotherapy (although the others do also). The determination of which type of Small Cell cancer is present is made by a pathologist using a microscope, to see what the cells look like. A pathologist is a physician who specializes in diagnosing disease from tissue samples. However, pathologist's won't always agree on the exact subtype. However, over 90% of pathologists will concur that a "Small Cell component" exists when shown a questionable specimen, and if ANY EXISTS, THE PATIENT SHOULD BE TREATED FOR SMALL CELL CANCER. Treatment is much different than for the other types of "epithelial" lung cancer. The fourth most common type is Large Cell carcinoma (15% of cases) which is actually a form of adenocarcinoma. Since the cells look much larger under a light microscope, however, it is given a separate category. It generally occurs in the periphery of the lung. Sometimes, the cancer does not look exactly like any of the above types, the cells are very primitive and aggressive looking. This is called "undifferentiated" cancer but careful analysis can often reveal the particular subtype. Nearly 30% of cancers may be "mixed", especially if advanced. As mentioned, if there is any Small Cell Cancer present, it should be treated as such. It is possible for other rare types of cancer to arise in or around the lungs. Examples are Lymphoma from the immune cells in the lung, Sarcoma from muscle, cartilage or fat, and Mesothelioma from the pleural lining of the lungs. Mesothelioma cancer can occur in the lining of the lungs, abdomen, or heart, and is only caused by previous exposure to asbestos. Mesothelioma has no known cure, and mesothelioma treatment options are unfortunately only a temporary means of controlling pain and symptoms. These conditions are all separate topics, with their treatment following that the the areas where they more commonly arise. Cancers from other areas may spread to the lungs, especially adenocarcinomas and sarcomas from other organs. The lungs are rich in blood and are a fertile area for other cancers to spread to. These are dealt with when considering the treatment for metastasis of these particular cancers. How Common is Lung Cancer? Each year there are about 170,000 new cases of lung cancer in the U.S.A. and 150,000 deaths attributable to this disease. Lung cancer is the most frequent fatal cancer, for both men and women, in the United States. Men are affected somewhat more frequently (100,000 cases/year) than women (70,000 cases/year). Worldwide, there are 1 million new cases per year. Over the past 5 decades the number of yearly cases has been increasing, and the worldwide incidence may double to 2 million per year in the coming decade. The average patient is 60 years old, and only 1% of cases are under 40 years old. Small Cell Cancer is the most rapidly increasing form of lung cancer and accounts for about 37,000 cases per year in the U.S.A . The proportion designated as Small Cell Cancer will vary in different studies depending on the methods of detection; in surgically treated patients the percentage is just 8% and in those diagnosed by fluid aspiration ("cytology") of the lungs, 30%. This is because surgery is inappropriate for most Small Cell Cancer patients. About 90% of patients have historically died from their disease but survivals are improving with the latest effective therapy as we will see. What Causes, or Increases the Risk For Small Cell Cancer? 1) Tobacco Smoking is the greatest risk factor for getting Small Cell Cancer, In large series of patients, fewer than 2% deny a history of heavy smoking. The risk begins to decline 5 years after quitting, and approaches normal at 20 years after quitting (but never exactly goes back to normal). Patients who quit smoking, even after diagnosis, tend to do better in treatment and live longer than those who continue smoking. 2) Radon Inhalation is associated with an increase in lung cancer. The radon breaks down into radioactive particles in the bronchi of the lungs, irritating the cells there, causing genetic damage, and leading them to divide. Radon tends to build up in unventilated Basements and Mine Shafts, uranium miners get more lung cancer; it is an occupational hazard. 3) Asbestos Inhalation in Mine workers, Pipe fitters, Shipbuilders, and people who worked with asbestos in insulation materials. The risk is especially high if patients both smoke tobacco and have asbestos exposure. Can Small Cell Lung Cancer be Prevented? Quitting smoking, and not being in close proximity of those who do, is the best way to prevent Small Cell Cancer. Even patients who have smoked for many years will see a decreased risk of heart attack from the day they quit smoking, and decreased risk of lung cancer after several years. A diet high in natural vitamins "A" and "E", and relatively low in fat, may be preventative for many "aero-digestive" cancers (those arising in the nose, mouth, throat, lungs and digestive system). Regular screening Chest X-rays do succeed in diagnosing lung cancer at earlier "stages", but have not been proven to increase survival from lung cancer. Nonetheless, it is reasonable for a person with high risk factors to get a chest X-ray as part of their annual physical, and to get one without delay if symptoms of lung cancer manifest. Lung cancer has been one of the most dreaded diagnosis in medicine, and has increased dramatically in the 20th century. The paired lungs are obviously vital to life, providing a surface for the blood to mix with oxygen. A person can live (with limitations) with a single lung, but in any lung, or "pulmonary" disease, conservation of healthy lung tissue is essential. At the same time, full eradication of a cancer problem is crucial to prevent rapid demise of the patient. It is critical to get proper treatment for a diagnosis of Small-Cell Lung Cancer, this can literally make the difference between life and death. Fortunately, new and better treatments are available, and particularly for Small Cell Lung Cancer new therapies are very encouraging. Understanding you options for a lung cancer problem will give you the peace of mind knowing that you have done everything possible for a happy outcome. Lung cancers, like mesothelioma, are among the most devastating forms of cancer. If you think you've been exposed to asbestos, contact a mesothelioma attorney to see if you can be compensated for your medical bills from asbestos related cancers. CancerAnswers' material explains, in plain English, the definition, types, frequency, symptoms, evaluation, historical and latest treatment for Small-Cell Lung Cancer. We describe the roles of surgery, radiation, chemotherapy and tell you their side-effects and results. We tell you everything you need to know to help you make the right choices today for a Small-Cell Lung Cancer problem. This is just an excerpt of CancerAnswers's report on Small-Cell Lung Cancer. Much more, including latest can be sent to you by mail when you order the complete Lung Cancer transcript at a nominal cost. Thank you for using CancerAnswers as your information resource.
last updated May 26, 2010 | ||||||||||||||||||||||||||||||||||||||||||||
