Lung cancer is a growth of abnormal cells inside the lung. These cells reproduce at a much faster rate than normal cells. The abnormal cells stick together and form a cluster or growth, known as a tumour. If the abnormal cells began growing in the lung, this is known as a primary lung tumour.
Cancers that begin in the lung are divided into 2 major types: non-small cell lung cancer and small cell lung cancer, depending on how the cells look under a microscope.
Non-small cell lung cancer generally spreads to other organs in the body at a slower rate than small cell lung cancer. Non-small cell lung cancer is the most common type of lung cancer, accounting for about 80 per cent of lung cancers. Small cell lung cancer accounts for about 20 per cent of all lung cancers.
As the number of men who smoke declines so the occurrence of lung cancer and the number of men dying from it are falling. However, lung cancer incidence and death rates among women have risen, reflecting a growing incidence in the number of women smoking cigarettes during the past few decades.
Cigarette smoking is the major cause of lung cancer. Up to 90 per cent of cases of the disease are caused by smoking. The longer a person has been smoking and the more packs of cigarettes smoked per day, the greater the risk. However, it is not known why one smoker develops lung cancer while another does not.
Workers exposed to industrial substances such as asbestos, nickel, chromium compounds, arsenic, polycyclic hydrocarbons and chloromethyl ether have a significantly high risk of developing lung cancer.
Research has also demonstrated the link between passive smoking and lung cancer.
Lung cancer is very difficult to detect at an early stage. Common symptoms include:
There are various treatment options for lung cancer (with different aims), including: surgery; chemotherapy; radiotherapy; and laser treatment.
Last Reviewed: 06 July 2009