INTRODUCTION Lung cancer may also be the most tragic cancer because in most cases, it might have been prevented, 87% of lung cancer cases are caused by smoking. Lung cancer has long been the most common cause of cancer death in men and since 1987 it has also become the most common cause of cancer death in women. Lung cancer is the second most commonly occurring form of cancer in most western countries and although the lung cancer incidence is less common in developing countries, the rapid increase in the popularity of smoking will see the number of lung cancer sufferers in those countries quickly catch up with the western world. Lung cancers can arise in any part of the lung, and 90%-95% of cancers of the lung are thought to arise from the epithelial, or lining cells of the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic carcinomas or bronchogenic cancers. The most common type of lung cancers are epidermoid carcinoma