Lung Cancer

Publié par happy-diet vendredi 21 mai 2010

Lung Cancer


A greater number of men and women, usually aged 65 to 75 years, died of lung cancer than any other cancer. The majority of lung cancer develops in the bronchi, that is to say, in the airways leading to lungs.

There are different types of lung cancer. The most common is called squamous cell carcinoma. Other types of lung cancer are small cell carcinoma or carcinoma cells "oat, adenocarcinoma and large cell carcinoma. Each type is evolving at a different rate and responds differently to treatment. Most lung cancers are smoking related, with the exception of adenocarcinoma. Often as a cancer that seat in other parts of the body spreads to the lungs.

Tobacco use is the major risk factor for lung cancer, and is responsible for more than 80% of lung cancers. The more a person has smoked for a long time and she smoked, the greater her risk of lung cancer. If a person stops smoking before cancer develops, lung tissue caused by smoking will start to heal. The risk of cancer in an ex-smoker will not be as low as in someone who never smoked, but it still decrease with time. Cigar smoking and pipe smoking causes almost the same degree of risk of lung cancer than cigarette smoking.

Even secondhand smoke, that is to say that the smoke inhaled from nearby smokers, can cause lung cancer. Non-smokers whose spouse smokes are at higher risk of 30% to be suffering from lung cancer than the spouse of someone who does not smoke. Recently, the Commission on Workplace Safety and Insurance against Accidents at Work (WSIB) has accepted the claim of non-smoker who worked in a smoking environment, and who had been diagnosed with lung cancer .

Living in an environment where the air is heavily polluted, or having a job that requires handling of radioactive minerals or asbestos can also increase the risk of lung cancer.

The research has led to better understand how these risk factors produce certain changes in the DNA of lung cells. These changes cause abnormal growth of cells and formation of cancerous tumors. DNA is the genetic material that contains instructions for all functions of cells, or almost. Some genes (ie parts of DNA) regulate the growth and cell division. Risk factors that we discussed earlier can trigger changes (mutations) of these genes, which then causes the appearance of cancer. Furthermore, the risk of suffering from certain forms of cancer (breast, ovarian, colorectal, and several other cancers) can be hereditary. However, scientists believe that in very many lung cancers, genetic mutations do not cause cancer.
Symptoms and Complications

The first symptom, and most common, lung cancer is coughing. When chronic bronchitis to lung cancer, the cough due to bronchitis will get worse. Cancer cells can grow at the expense of the blood vessels, which results in the presence of blood in the sputum (secretions expelled by coughing). Cancer can still develop at the expense of the bronchi or put pressure on them, reducing their diameter and cause wheezing. Cancer can also develop in the chest wall and cause pain in the chest. The tumor can also cause pneumonia, with symptoms of cough, fever, chest pain and shortness of breath. People with lung cancer in advanced stage their appetite, feel weak and lose weight.

Lung cancer can invade surrounding tissues to the lungs or other distant tissues, eg liver, brain and bones, which also causes pain. When the cancer invades the lungs, the amount of oxygen in the blood decreases, which leads to heart failure. The tumor may also develop in a vein that carries blood from the upper body towards the heart, and she can cover this vein. This condition is known as compression syndrome of the superior vena cava and is characterized by the reflux of blood in the veins of the face, neck and upper chest and the veins to swell.

Cancer can cause fluid accumulation in the envelopes of the heart or lungs, making breathing very difficult. Cancerous cells sometimes pressure on the lung, causing it to crush (collapse) when the tumor presses on the spinal cord, the patient experiences pain or the loss of nerve function. Some cancers also release hormones that can affect metabolism.

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