Lung cancer is one of the fastest-spreading cancers of all. Also known as ‘lung carcinoma’, lung cancer is a malignant tumor growing uncontrollably in the lungs. Most commonly caused as a result of regular smoking. Other causes are interaction with carcinogenic substances including air pollutants. These cases are often caused by a combination of genetic factors and exposure to radon gas, asbestos, second-hand smoke, or other forms of air pollution. Lung cancers are diagnosed through chest radiographs and computed tomography (CT) scans, and through biopsies.
There are 3 main types of lung cancer, namely non-small cell lung cancer, small cell lung cancer, and lung carcinoid tumor.
Cigarette-smoking is the biggest risk-factor to lung cancer
Non-small cell lung cancer
While it is the most common form of cancer, it is also the form which grows and spreads slower than the next most common type of lung cancer (small cell lung cancer). This type of cancer is further divided into 3 sub-types:
1. Adenocarcinoma: this type of NSCLC begins in the mucus-producing air sacs within the lungs, and and is the most common type of lung cancer for smokers, non-smokers, and people younger than 45 years.
2. Squamous cell carcinoma: this NSCLC is primarily caused by smoking, and originates in the squamous cells, which are types of skin cell. This type of cancer is more common in men than in women.
3. Large cell (undifferentiated) carcinoma: this type of NSCLC is named so because they appear large and round when viewed under a microscope. This type spreads more quickly, and is responsible for 10-15% of lung cancers.
Small cell lung cancer
Compared to the non-small cell lung type, this type of cancer typically spreads much faster. Its most common symptoms include a cough, weigh-loss, and dyspnea (labored breathing). Because of its appearance when examined, it is sometimes called “oat cell carcinoma”. This type of cancer is also more frequently metastatic (formation of secondary malignant growths). This type of cancer typically affects 10-15% of all lung cancer patients.
Lung carcinoid tumor
These are the least common of all lung cancers. Usually treated surgically, the symptoms of this cancer typically include a cough and a discharge of bloody sputum during the cough (hemoptysis). These tumors are usually 5% of all lung cancers and are slow to spread.
The prognosis (outlook) for lung cancer patients usually depends on the type of cancer and the stage of the cancer. Treatment outcomes also depend on the quality of health care provided. Interestingly, lung cancer is the most common form of cancer in men, and third most common in women (by incidence).