Lung Cancer
In its most basic form, lung cancer represents the uncontrolled cell proliferation of lung tissues.  The abnormal area may stay in the lung or may metastasize to other parts of the body.  Most of the lung cancers found are called carcinomas of the lung and are derived from the epithelial cells of the lung.  This is a disease that is the number one cause of cancer deaths in men and the number two cause of cancer deaths in women.  The basic symptoms include being short of breath, having a cough, coughing up blood and loss of weight.
The two main types of lung cancer are non-small cell cancer and small cell cancer.  It is important to distinguish between the two because the treatments are very different.  For example, non-small celled cancers are often treated using surgery while small cell cancer is more responsive to radiation and chemotherapy.  The most common cause of these cancers is prolonged exposure to cigarette smoke or other kinds of tobacco smoke.  In nonsmokers, accounting for up to 20% of cases, the causes are believed to be genetic, due to radon gas or asbestos or exposure to air pollution.   
Lung cancer is best seen on chest x-ray or CT scan of the chest.  Biopsy through a bronchoscope or through CT guidance also helps diagnose the disease.  Doctors determine prognosis depending upon the histology of the tissue, the stage and the grade of the cancer.  The range of treatments includes chemotherapy, surgery and radiation.   The five year survival chances are 14%. 
Non-Small Cell Carcinoma
This occurs as a group with three main subtypes. These include squamous cell carcinoma, large cell carcinoma, and adenocarcinoma.  Squamous cell carcinomas account for 31% of lung cancers and generally start near a large bronchus.  There is often cavitation and central necrosis in the middle of the cancer.  They have the propensity to grow more slowly than other cancers.
Adenocarcinomas comprise 29% of cancers of the lung.  It is almost always originating in peripheral lung parenchyma.  Most cases are associated with smoking but a fair amount of non-smoking related lung cancers are also adenocarcinoma.  There is a subtype of adenocarcinoma called bronchiolalveolar
Small Cell Carcinoma
Small cell carcinoma is also called oat cell carcinoma and is less common than large cell carcinomas.  It starts in the large airways of the lung and grows quickly, often becoming very large.  While it is more sensitive than large cell carcinoma to chemotherapy, its overall survival rate is much lower.  This is a kind of cancer that is highly associated with smokers. 
Metastatic Cancer
The lung is a common site for cancers that originated at other sites, making them metastatic cancers.  One of the primary places of origin of these cancers is the breast or the colon.  Primary lung cancers commonly metastasize to places like the adrenal glands, the brain, the liver and to the bone. 
Signs and Symptoms
Signs and symptoms of lung cancer include shortness of breath, chronic coughing, coughing up blood, pain in the chest, gradual weight loss, fatigue, poor appetite, clubbing of the fingernails, hoarse voice or difficulty swallowing.  As the disease progresses, it may block the airways resulting in worsening breathing problems and secondary pneumonias. 
Treatment
The treatment of the disease depends on the cellular type, degree of spread of the disease and the patient’s performance ability.  Commonly used treatments include chemotherapy, surgery and radiation therapy.  Surgery alone has an operative death rate of about 4.4%. Small cell cancer has not been found to be helped by surgery so radiation and chemotherapy are used instead. 
Studies have shown that there is oxidative stress in all types of lung cancer.  Glutathione levels were found to be reduced, particularly with non-small cell cancer.  This means that the treatment of lung cancer with glutathione can be particularly helpful.