ABSTRACT
Prevention is traditionally classified into primary, secondary and tertiary prevention. Primary prevention occurs when attempts are made to reduce or remove the cause of a disease. Secondary prevention encompasses the early detection and treatment of disease. Tertiary prevention aims to reduce the impact of established disease. The main cause of lung cancer is smoking. It has been reported that patients who develop lung cancer eat less fruit and vegetables than do members of the healthy population. The main risk factor for cancer of the oesophagus in the Western world is smoking. Alcohol consumption in the range 40-100 grams per day produces a three- to eightfold increase in risk, with synergistic effects with smoking. Asbestos has been recognised for several decades as a cause of lung cancer and mesothelioma of the lung and peritoneum. Worldwide, the most important infectious causes of cancer are hepatitis B and C viruses, which are both associated with hepatic cancer.
