Lung Cancer affects a life-sustaining system of the body, the respiratory system. It is one of the commonest malignancies in the world. Lung Cancer develops when normal lungs cells sustain genetic damage that eventually leads to uncontrolled cell proliferation. like all cancers, lung cancers cells have the ability to invade neighboring tissues and spread or metastasize to distant parts of the body. Left untreated, lung cancer eventually causes death.
With increasing prevalence of smoking, lung cancer has reached epidemic proportions in India. While there are more cases of lung cancer diagnosed in men, the numbers of woman being diagnosed has increased. Lung cancer is rarely diagnosed in younger than 40, but incidence rises steeply thereafter peaking in people aged 75-84 years. Most cases occur in people over the age of 60.
The lungs are highly vascularized organs, meaning they have many blood vessels running through them. This vascularization is needed for the quick exchange of oxygen and carbon dioxide that takes place with each breath. Among people with lung cancer, these blood vessels provide many convenient routes for lung cancer cells to travel to other pats of the body. Most cancer cells that enter the bloodstream die. However, if lung cancer cells survive and begin to grow in a site distant from the lungs, they produce metastatic tumors. Lung Cancer tends to spread or metastasize very early; therefore it is a very life threatening cancer and one of the most difficult cancers to treat. While lung cancer can spread to any organ in the body, certain organs – particularly the adrenal glands, liver, brain, and bone – are the most common sites for lung cancer metastasis.
The lung also is a very common site for metastasis from tumors in other parts of the body. Tumor metastasis are made up of the same types of the cells as the original (primary) tumor. For Example- If Lung cancers can arise in any part of the lung, but 90%-95% of cancers of the lung are thought to arise from the epithelial-cells, the cells lining the larger and the smaller airways (bronchi & bronchioles); for this reasons, lung cancers are sometime called bronchogenic cancers. Lung cancer development is a multi-factorial process. The majority of lung cancers occur in people who are either current or former smokers. While the relationship between smoking and lung cancer is well established, other factors also come to play
There are two main types of lung cancer- non-small-cell (NSCLS) and small-cell (SCLC), which develop and are treated in different ways. .