A. LUNG CANCER: Definition: According to the National Cancer Institute (2009), lung cancer refers to the uncontrolled and abnormal proliferation of lung tissue, usually in the cells lining the airways1. This occurs when there is excessive growth of cells present in the lungs, leading to a variety of clinical symptoms. Classification: The International Classification of Diseases, ICD-10, classifies lung cancer under C34 as a malignant tumor of the bronchi and lung2. When reporting routine statistics, tumors of the lung and bronchi are grouped with those of the trachea C333. Pathology and clinical features: Lung cancer occurs mainly in adults between 45 and 75 years of age and approximately 80 to 90% of all cases are due to tobacco. smoking as the main etiological factor4-6. The risk of developing lung cancer is higher in those who start smoking at a young age, as well as in heavy smokers than in light smokers5. Other risk factors include exposure to radon, asbestos, uranium and pitchblende, chrome and nickel refiners, welders and workers exposed to halogenated ethers. 5. There are basically two types of lung cancer, small cell tumor and non-small cell tumor. which can be differentiated under a microscope. The main clinical features of lung cancer include cough (80%), hemoptysis (70%), dyspnea (60%), and chest pain (40%). Others include recurrent or slowly resolving pneumonia, weight loss, anemia, anorexia, and enlarged lymph nodes. 7.Epidemiology: Lung cancer is the second most commonly diagnosed cancer in the UK (excluding non-melanoma skin cancers) and is more common in men. than women (figure 1.0). Lung cancer accounted for approximately 39,000 (Figure 1.3) of all cancer cases diagnosed in the UK in the middle of the article......arch/articlesBySubject/displaystory.cfm?subjectid=349008&story_id=E1_TPSGGQRP. Accessed 11/28/2009.22. Why people smoke Available at: http://healthliteracy.worlded.org/docs/tobacco/Unit3/1why_people_smoke.html. Accessed 11/29/2009.23. Walker MS, Vidrine DJ, Gritz ER, Larsen RJ, Yan Y, Govindan R et al. Smoking relapse during the first year after treatment for early-stage non-small cell lung cancer. Epidemiological biomarkers of cancer, previous 2006; Dec; 15(12):2370-7.24. Britain quits smoking - Times Online Available at: http://www.timesonline.co.uk/tol/news/uk/article730913.ece. Accessed 11/28/2009.25. Get help to stop smoking – NHS Stop Smoking Campaign – Stop Smoking Available at: http://www.canstopsmoking.com/. Accessed 11/29/2009.26. Associations of smoking and lung cancer Available at: http://www.medscape.com/viewarticle/576699. Accessed 11/28/2009