Lung cancer is one of the most common kinds of cancer. In fact, it is the most common cancer in the US, with over 220,000 people being diagnosed with it each year. The number of deaths caused by this condition is around 150,000 per annum, in the US alone. These are the main reasons why learning the most important things about the condition is essential.Lung cancer is characterized by the transformation of normal lung cells into abnormal cells. These abnormal cells grow rapidly and uncontrollably to form a malignant tumor. This usually happens in walls of the bronchi.There are over 20 types of lung cancer, but four have been identified as the most commonly occurring. These four have been separated into two groups; non-small cell lung cancer and small cell lung cancer. The most common kind of non-small cell cancer of the lungs is adenocarcinoma. It accounts for around 40% of all cases. The most typical thing for it is that it is formed in the outer edges of the lungs and in the smaller airways, in particular.Squamous cell carcinoma is another type of non-small cell lung cancer. It is responsible for approximately 30% of all cases. The tumor usually grows in the central bronchi, which are the largest branches of the bronchi tree. This form of the condition is the easiest to detect and to treat successfully.The large-cell carcinomas affect between 10% and 15% of all lung cancer patients. These tumors usually grown in the outer edges of the lungs and tend to spread quickly to nearby tissues and lymph nodes.Small cell lung cancer is not particularly common, but it is extremely aggressive. It starts in the central bronchi, but has no noticeable symptoms until the later stages of the tumor development. Furthermore, it tends to spread rapidly to other organs and tissues.Lung cancer is directly linked to smoking and cigarette smoking, in particular. Roughly 4 out of 5 patients are smokers. It has been estimated that up to 90% of all cases are arising directly from the use of tobacco. All these facts suggest that smokers have the highest risk of developing this condition. Pipe and tobacco smokers as well as passive smokers are also more likely to develop this type of cancer. The higher risk is associated with the fact that tobacco contains various cancer-causing and carcinogenic chemical compounds.Asbestos exposure is also correlated to the development of lung cancer. Thankfully, the use of this material is limited or completely banned in many countries. The exposure to radiation coming from the decay of radon gas is also a serious risk factor. Around 10% of all cases of the condition are estimated to be due to this factor. The presence of specific genes may also increase the risk in some individuals.Approximately 25% of all people who have lung cancer do not experience any symptoms. Despite this, there are some common warning signs associated with the condition. Coughing up blood is the most disturbing symptom. Smokers and ex-smokers might start having a new cough that is persistent and untypical for them. Chest pain and shortness of breath are other common warning signs. Having repeated respiratory infections might also signal that you have the condition.Lung cancer is diagnosed after a series of tests. The doctor usually performs an x-ray first, after noticing disturbing symptoms. A CT scan of the chest is also performed. A biopsy is done to confirm the condition. Further tests are necessary to determine the type of lung cancer the patient has.Lung cancer treatment usually begins with surgery. The surgeons may remove only the tumor, the tumor with part of the lung or the whole lung. Cryosurgery, the killing of the tumor by freezing it, is also an option. The treatment usually continues with chemotherapy and radiation therapy. It should be pointed out that number of patients surviving five years after treatment is around 15%. For this reason, prevention is extremely important.The best method for this cancer prevention is not smoking. If you smoke, but quit now; your risk will start decreasing automatically. It has been estimated that your risk will be similar to a nonsmoker after 15 years of cessation. Try to avoid exposure to cigarette smoke. Take protective measures if you work with dangerous material such as asbestos.