According to WHO data, cancer accounts for 7.1 million deaths annually (12.5% of the global total). The estimated number of new cases is expected to rise from 10 million in 2000 to 15 million by 2020. Cancer is thus becoming an increasingly important factor in the global burden of disease. Yet, at least one-third of cancer cases that occur annually throughout the world could be prevented. Personal habits, such as tobacco use, dietary and physical activity patterns - as well as occupational and environmental conditions - rather than genetic factors, play the major roles in the development of cancer. While tobacco use is the single largest causative factor -accounting for about 30% of all cancer deaths in developed countries, dietary modification and regular physical activity are significant elements in cancer prevention and control. An important source of information and classification on the occurrence of cancer worldwide is the WHO funded International Agency for Research on Cancer (IARC). Its mission is to coordinate and conduct research on the causes of human cancer, the mechanisms of carcinogenesis, and to develop scientific strategies for cancer control.
Children are more prone to biological events potentially related to carcinogenesis, due to greater exposures, immature detoxification mechanisms and higher cell proliferation. In addition, exposure to carcinogens during childhood can reflect on cancer occurrence later in life. In European countries, 1 out of 500 children is estimated to be diagnosed with cancer before the age of 15. For some exposures such as exposure to ionising radiation and excessive exposure to sun-light, the scientific evidence for casuality is clear-cut. For a number of other chemicals, physical and biological agents, knowledge as to their ability to induce cancer in children or later in life ranges between limited evidence (e.g. vehicle exhausts) and suspicion (pesticides, environmental tobacco smoke, radiofrequency and microwave). These are also some of the conclusions of the Baseline report on Childhood cancer produced by the Techical Working Group in the framework of the SCALE process.
However, lack of full proof of carcinogenity should not prevent the implementation of measures intended to reduce to a minimum childhood exposures, through legislative measures and risk communication.