Epidemiology of cancer and principles of prevention

Neoplasms include several hundreds of diseases, which can be distinguished by localization, morphology, clinical behaviour and response to therapy. The number of new cases of cancer which occurred worldwide in 2008 has been estimated at about 12,700,000. Of these, 6,600,000 occurred in men and 6,000,000 in women. About 5,600,000 cases occurred in high-income countries (North America, Japan, Europe including Russia, Australia and New Zealand) and 7,100,000 in low- and middle-income countries. Among men, lung, stomach, colorectal, prostate and liver cancer s are the most common malignant neoplasms, while breast, colorectal, cervical, lung and stomach are the most common neoplasms among women. Analytical studies have shown the causal role of several exposures in the aetiology of malignant neoplasms: The major causes of human cancer are tobacco smoking, dietary factors, obesity, alcohol drinking, infectious agents, occupation and pollution, reproductive factors and exogenous hormones, perinatal and growth factors, ionizing and nonionizing radiations, medical procedures and drugs, besides genetic factors. Consequently, the prevention of cancer includes primary and secondary prevention programmes. The main goal of primary prevention is to reduce the incidence of cancer through the reduction of exposure to risk factors for cancer at the population level, while secondary prevention takes place through the early detection of cancer. Where feasible, primary prevention programmes are largely cost-effective, i.e. the reduction of the burden of disease is achieved with a reasonable money investment, while this is not always the case for secondary prevention programmes. In this chapter, we aim to describe the current burden of cancer and the main health policies available, in order to provide key elements for public health professionals.