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" shape 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 brochi 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. 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, and compromise of 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 peripherapy of the lungs, as opposed to squamous cell which commonly has a more central location along the bronchioles. The third most common type is small cell carcinoma, also called "oat cell" (20% of cases). Its treatment is much different than for the other types of "epithelial" lung cancer, and it is considered a different topic. The fourth most common type islarge 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. 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, andmesothelioma from the pleural lining of the lungs. 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 about170,000 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. About 90% of patients have historically died from their disease but survivals are improving with the latest effective therapy. What Causes, or Increases the Risk for Lung Cancer? Like any cancer, the exact reason why one particular person gets lung cancer and another does not remains unknown. However, certain factors are strongly correlated with with an increase in lung cancer, when groups of patients are studied: 1) Tobacco Smoking is the best known risk factor for lung cancer. The risk goes up with the number of cigarettes smoked. Doctors calculate usage as "pack-years" which means multiplying average packs per day with number of years smoked. Increasing from one to two packs per day smoked increases the risk 4 times, (from 55 cases/100,000 smokers/year to 217 cases/100,000 smokers/year). It takes 5 years after quitting smoking for the risk to appreciably decrease, and at 15 years after the risk approaches the never-smoked level. Second hand smoke has gotten a lot of press lately, with some claims that the risk of cancer is up to 20 times greater than the smoker themselves! This is a distortion based upon the observation that unfiltered smoke from the tip of a cigarette has more cancer causing chemicals ("carcinogens") than filtered smoke. Nonetheless, an higher risk for lung cancer amoung spouses of smokers and people who spent many years working in enclosed, smoke-filled offices is well-documented. However, the chance of getting lung cancer from occasional casual exposure to a smokers "second-hand" smoke is almost zero. Driving down a crowded freeway exposes our lungs to more carcinogens from auto exhaust than "second-hand" smoke. Inarguably, lung cancer has skyrocketed with the popularity of cigarettes. Before the year 1850, only about 200 cases of lung cancer were even known of! 2) Carcinogen Exposures besided tobacco smoke that are linked with lung cancer include asbestos, coal tar fumes, nickel, chromium, and arsenic. There is a higher risk in coal miners. There used to be a much higher risk in people who worked in talc and soap dust factories, before the air there was filtered. Any small particle that gets into the lungs and irritates over time, promoting cell division, increases the risk for lung cancer. 3) Radiation Exposure is the next highest risk factor for lung cancer. The most common type is radon, a radioactive gas given off when radium disintegrates. The problem is when this gas builds up in enclosed areas, like basements. When radon gets into the lungs it undergoes further disintegration with release of high-energy particles that damage the DNA in lung cells, possibly leading to uncontrolled division (cancer). Test kits are available to determine if radon is a problem in your home. Other forms of radiation to the lungs come from the "polonium" in tobacco smoke, from natural backround radiation (cosmic rays, radiation from mineral deposits in the earth, and some potassium-40 we all eat) and from medical procedures. The chance of getting lung cancer from a chest X-ray is less than 1 in a million. The best protection against lung radiation is to check our basements for radon, and not to smoke tobacco. 4) Miscellaneous Risks Factors include old scars in the lungs (such as from tuberculosis), the rheumatological disease scleroderma, and a slight familial tendency for susceptibility to getting lung cancer, especially after carcinogen exposure. Most cancers are a combination of some external hazard, such as a virus, chemical or radiation, in conjunction with a genetic susceptibility to developing a cancer when exposed to such hazards. Does Screening Help for Lung Cancer? A large National Cancer Institute study showed that when 30,000 male smokers had chest X-rays and sputum tests to look for lung cancer, more of them had the disease picked up early, but no survival benefit was seen from screening. Thus, we don't routinely screen for lung cancer in the absence of symptoms. Nevertheless, it is reasonable to screen patients with high risk factors, to pick up the disease early. As we will see, early disease is much more successfully treated than advanced cancer. What are the Symptoms of Lung Cancer? Like any cancer,very early lung cancer has no symptoms, since there are too few cancer cells to interfere with normal body functioning. As the cancer gets larger, symptoms increase. Lung cancer has mushroomed in the past 3 decades to become a major health problem. While once viewed as always fatal, new research has led to therapies that give some real hope to the lung cancer patient. It is crucial to be well-educated about this disease to help you choose the proper therapy. Selecting the right treatment can literally make the difference between life and death. It is important to have the peace-of-mind knowing that you have done everything possible to help fight lung cancer successfully. CancerAnswers's materials explain, in plain English, the definition, types, frequency, risk factors, symptoms, historic and latest effective treatment for lung cancer. We describe surgery, radiation, chemotherapy and immune therapies. We tell you everything you must know to help make the right choices today for a lung cancer problem. If you're suffering from lung cancer, you may have mesothelioma? You may want to get in contact with asbestos lawyers to help fight for what you deserve in a lawsuit. To get more information about a mesothelioma lawsuit, just look online.
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 last updated 3.20.7 |