A greater number of men and women, generally 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 upper airway leading to the lungs. There are different categories of lung cancer. The most common is lung cancer “non-small cell”, which includes adenocarcinoma, large cell carcinoma and squamous cell carcinoma. The other type of lung cancer is that of small cell carcinoma (or carcinoma cells in “oat”).
Each category 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 established in other parts of the body spreads to the lungs.
Smoking is the main risk factor for lung cancer, and is the cause of over 80% of lung cancers. More a person has smoked for a long time and she smokes, the greater the risk of lung cancer. If you quit smoking before cancer develops, the lung tissue damage caused by smoking begin to heal. The risk of cancer for an ex-smoker will not be as low as for a person who never smoked, but it will decline over time anyway. The use of the cigar and pipe smoking causes almost the same degree of risk of lung cancer as cigarette smoking.
Even second-hand smoke, that is to say that a person inhales the smoke in the presence of a smoker, can cause lung cancer. Non-smokers whose spouse smokes are at higher risk of 30% of suffering from lung cancer than the spouse of a person who does not smoke.
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. Research has better understand how these risk factors produce certain changes in DNA in lung cells. These changes induce abnormal growth of cells and the formation of cancerous tumors.
DNA is the genetic material that contains instructions for all functions of cells, or almost. Some genes (that is to say parts of DNA) regulate growth and cell division. Risk factors that we discussed earlier can trigger changes, also called mutations of these genes, which will then cause the development of cancer. Moreover, the risk of suffering from certain forms of cancer (eg. Breast cancer, ovarian, colorectal cancer, and many others) can be hereditary. However, scientists believe that in many lung cancer, heritable genetic mutations do not cause cancer.
Symptoms and Complications
The first symptom, and most common, lung cancer is coughing. When chronic bronchitis is followed by lung cancer, cough caused by bronchitis worsens. Cancer cells can develop in blood vessels, which results in the presence of blood in the sputum (secretions coughed up). 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 chest pain. The tumor can also cause pneumonia, which is accompanied by cough, fever, chest pain and shortness of breath. People with lung cancer have advanced more appetite, are weakened and lose weight.
Lung cancer can invade adjacent tissues to the lungs or other distant tissues such as liver, brain and bones, which also causes pain. The tumor may also develop in a vein that returns blood the upper body to the heart, and the block. This condition, called compression syndrome of the superior vena cava, is characterized by the backflow of blood into the veins of the face, neck and upper chest and swelling of these veins.
Cancer can cause fluid accumulation in the envelopes of the heart or lungs, making breathing very difficult. Cancer cells may also exert pressure on the lungs and can pinch (collapse) ; When the tumor presses on the spinal cord, the patient feels pain or has a disorder of nerve function. Some cancers produce more hormones that can affect metabolism.