Trends in primary and secondary prevention

Approximately 75% of cancers are due to lifestyle and environmental factors. However, chemical pollution of the air and food as well as ionizing radiations are minor causes of cancer. The aim of this article is to briefly review the main causes of cancer which have been identified and to assess the cost-benefit ratio of each of the actions which can be undertaken. The clear conclusion is that the main effort should be directed against tobacco. A readily achievable goal for the end of the century is a 30% reduction in tobacco consumption which would result in a 10% reduction of the cancer toll. However, other actions should also be undertaken. Epidemiologic surveys, experimental research, health education at school from a very young age, and information of practitioners are necessary in order to improve prevention of cancer.