tailieunhanh - Cancer Malcolm R Alison, Imperial College School of Medicine, London, UK

Cancer registries can play an important role in monitoring and evalu- ating the effectiveness of primary prevention measures. As mentioned in Section , trends in cancer incidence can be related to changes over time in exposure to risk factors. Occasionally, when implementation has been confined to one area, comparisons of the changes in the intervention area versus ‘control’ areas may be possible. It should be kept in mind when interpreting such relationships that it takes considerable time (generally decades) for the effect of a change in exposure to be reflected in cancer incidence data | Cancer Malcolm R Alison Imperial College School of Medicine London UK Introductory article Article Contents Cancer is a potentially fatal disease caused mainly by environmental factors that mutate genes encoding critical cell-regulatory proteins. The resultant aberrant cell behaviour leads to expansive masses of abnormal cells that destroy surrounding normal tissue and can spread to vital organs resulting in disseminated disease commonly a harbinger of imminent patient death. Overview Cancer is a complex genetic disease that is caused primarily by environmental factors. The cancer-causing agents carcinogens can be present in food and water in the air and in chemicals and sunlight that people are exposed to. Since epithelial cells cover the skin line the respiratory and alimentary tracts and metabolize ingested carcinogens it is not surprising that over 90 of cancers occur in epithelia. The causes of serious ill-health in the world are changing. Infection as a major cause is giving way to noncommunicable diseases such as cardiovascular disease and cancer. In 1996 there were 10 million new cancer cases worldwide and six million deaths attributed to cancer. In 2020 there are predicted to be 20 million new cases and 12 million deaths. Part of the reason for this is that life expectancy is steadily rising and most cancers are more common in an ageing population. More significantly a globalization of unhealthy lifestyles particularly cigarette smoking and the adoption of many features of the modern Western diet high fat low fibre content will increase cancer incidence. Tobacco use and diet each account for about 30 of new cancer cases with infection associated with a further 15 thus much of cancer is preventable. No individual can guarantee not to contract the disease but it is so strongly linked to diet and lifestyle that there are plenty of positive steps that can be taken to reduce the chances eat more fruit and vegetables reduce the intake of red meat and definitely