What is lung cancer?
The lungs are the organs found in the chest cavity and is divided into sections called lobes. There are 2 lobes in the left lung and three lobes in the right lung. A membrane called pleura covers the lungs. The pleura inner layer protects the lungs and helps separate the lobes, whereas the outside layer is attached the chest wall. The fluid that fills the layer space acts as a lubricant allowing the lungs to expand and contract in smooth movements. Lung cancer can develop in any of these areas.
Respiration occurs when air passes into the trachea or windpipe from the nose or mouth. The trachea divides into bronchi which lead into each lung. Further, the bronchi split into smaller bronchioles similar to the branches on a tree. The bronchioles end up in small air sacs called alveoli. Oxygen from the air flows into these air sacs to the blood. At the same time, carbon dioxide travels from the blood to the lungs and is exhaled from the body.
Lung cancer in India is one of the most common cancer. It is the uncontrolled growth of abnormal cells in one or both lungs. Such abnormal cells do not perform normal lung cell functions and do not develop into healthy lung tissue. The abnormal cells can develop tumors as they expand and interfere with the functioning of the lung. Typically, lung cancers originate in the cells lining the bronchi and lung sections such as the bronchioles or alveoli.
Lung cancers are typically classified into two major groups called small cell and non-small cell. Non-small cell lung cancer is more common than small cell lung cancer. People may also have cancer traveling from another part of their body, or metastasizing into their lungs. This is called secondary lung cancer because the lungs are a secondary site relative to the cancer ‘s original primary location.
Smoking is one of the major causes of most lung cancers in both smokers and those exposed to second-hand smoke. Yet lung cancer also occurs in people who have never smoked and who have never been exposed to second-hand smoke for longer period of time. In such cases, lung cancer may not have a specific cause.
What causes lung cancer?
There are various lung cancer causes including:
- Prior history of lung cancer
- Passive smoking
- Exposure to radon gas
- Exposure to asbestos fibres
- Family history of lung cancer
- Lung diseases
- Air pollution
- Exposure to diesel exhaust