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Exposure to carcinogens, such as those present in tobacco smoke, immediately causes small changes to the tissue lining the bronchi of the lungs (the bronchial mucous membrane). This effect is cumulative, and over time with continued exposure more and more tissue gets damaged until a tumour develops. If the tumour grows inwards it may obstruct the air passageway, causing breathing difficulties. The lungs may then collapse and infections can develop, leading to lung abscess. The patient here would start to cough up blood-stained material. However, if the tumour grows outwards in to the lung it may not even be noticed by the patient before it starts to spread to other parts of the body. Common symptons include: coughing up blood or lung-material; a bad, chronic cough; wheezing; chest pains; weight loss or loss of appetite; and shortness of breath.
There are two main types of lung cancer categorised by the size of the malignant cells seen under a microscope: small and non-small cell lung cancer. This classification although based on simple pathomorphological criteria has very important implications for clinical management and prognosis of the disease.
Small cell types:
Small cell carcinoma (also called oat cell carcinoma) is the less common form of lung cancer, making up 20% of cases. It tends to start in the larger breathing tubes and grows rapidly becoming quite large.
Non-small cell types:
Epidermoid carcinoma (or Squamous cell carcinoma) also starts in the larger breathing tubes but grows slower meaning that the size of these tumours varies when on diagnosis.
Large cell carcinoma is a fast-growing form that grows near the surface of the lung.
The listed types add up to 90% of all cases of lung cancer. Other forms include carcinoid, cylindroma, mucoepidermoid and malignant mesothelioma.
Cancer death rates in the United States. There are four major reasons why people get lung cancer (and actually cancer in general):
Passive smoking, whereby exhaled smoke is taken up by other people, has recently been identified as a much larger cause of lung cancer in non-smokers than previously believed. The US Environmental Protection Agency (EPA) in 1993 concluded that about 3,000 lung-cancer related deaths were caused by passive smoking every year, however the true extent is still being contested among scientists.
AsbestosThis page is about the group of minerals, for the Regional County Municipality in Quebec, see Asbestos Regional County Municipality, Quebec Asbestos (Greek a-, "not"; sbestos, "extinguishable") is a group of fibrous metamorphic minerals. The name is deriv is another popularly known carcinogen mainly for mesothelioma (affecting the mesothelium lining lungs, abdomen or heart.) Often this exposure happens to people unavoidably through their work. RadonAstatine Radon Xe Rn Uuo Full table General Name, Symbol, NumberRadon, Rn, 86 Chemical series Noble gases Group, Period, Block 18 (VIIIA), 6 , p Density, Hardness 9. 73 kg/m3 (273 K), NA Appearance colorless Atomic properties Atomic weight [222] amu Atomi is a colourless and odorless gas derived from the breakdown of radioactive radiumFrancium Radium Actinium Ba Ra Full table General Name, Symbol, NumberRadium, Ra, 88 Series Alkali earth metals Group, Period, Block 2(IIA), 7 , s Density, Hardness 5000 kg/m3, no data Appearance Silvery white metallic Atomic Properties Atomic weight (226, which in turn is the decayed product of uraniumUranium is a chemical element in the periodic table that has the symbol U and atomic number 92. A heavy, silvery-white, toxic, metallic , and naturally- radioactive element, uranium belongs to the actinide series and its isotope uranium-235 is used as the, found in the earth's crust . It is the second major cause of lung cancer after smoking. This radiation ionises genetic material, causing mutations that sometimes become cancerous. Radon gas levels vary over where you live. In areas such as CornwallCornwall ( Cornish: Kernow is the part of Great Britain's south-west peninsula that is west of the River Tamar. It is generally regarded as a county of, and a part of England, although advocates of Cornish independence regard it as a separate nation, and in the UK, radon gas is a major problem, and fans have to be installed to drive out the gas. In the US the EPA estimated that 1 in 15 homes have radon levels above the recommended standard. Oncogenes are genes which is believed make people more susceptible to cancer. Proto-oncogenes are believed to turn in to oncogenes when exposed to particular carcinogens. Viruses are suspected to cause cancer in humans, as this link has already been proven in animals.| Politics | Business | Finance |
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