WHO histological classification of tumours of the lung

With more than 1.1 million deaths annually worldwide, lung cancer is the most frequent and one of the most deadly cancer types. In men, 85-90% of cases can be attributed to tobacco smoking. Some Western countries in which the smoking habit took off about 100 years ago, tobacco control programmes have led to a significant decline in mortality. Unfortunately, the habit has now spread to many newly industrialized countries, particularly in Asia, and in Europe, there is a worrying trend of increasing smoking prevalence in young women. The prognosis of lung cancer is still poor, with 5-years survival rates of approximately 10% in most countries. Thus, primary prevention by not starting or by stopping smoking remains the most promising approach. The association between smoking and lung cancer is not solely based on epidemiological studies. Lung tumours of smokers frequently contain a typical, though not specific, molecular fingerprint in the form of G:C > T:A mutations in the TP53 gene which are probably caused by benzo[a]pyrene, one of the many carcinogens in tobacco smoke. WHO histological classification of tumours of the lung __________ 1 Morphology code of the International Classification of Diseases for Oncology (ICD-O) {6} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded /0 for benign tumours, /3 for malignant tumours, and /1 for borderline or uncertain behaviour.