EPIDEMIOLOGY FOR CANCER PREVENTION - SOME CONSIDERATIONS ON THE ETHICS OF PUBLIC-HEALTH INTERVENTIONS

About 5 million cancer deaths occur each year in the world, and many more cancer incident cases arise. It is estimated that at least 80 % of these cancers could be avoided, based upon currently available epidemiological knowledge. Such a result could be achieved through modification of life-style and, to a much lesser extent, of the general environment. Therefore, prevention of cancer is a realistic and attainable goal. Two complementary approaches can be envisaged. The first would be an holistic enterprise aiming at health promotion in general. This can be achieved by adopting a life-style favourable to physical, moral and social well-being and consists of avoiding recognized cancer risks by the elimination of smoking, moderation in alcohol consumption, modification of diet and the suppression of occupational and environmental carcinogens. Public health programmes must be set up as soon and as widely as possible and should be directed primarily at children and be seriously evaluated. Doctors and health professionals have a major role to play in this important effort. By contrast, pharmacoprevention is only at a preliminary research stage. With the exception of immunization which has demonstrated its efficacy in infectious diseases and looks promising for the prevention of virus-associated cancers, other proposed chemopreventive agents are not yet ready for use in the population at large. Vitamin supplementation and particularly antihormones have been proposed for the prevention of cancers. Potential or demonstrated iatrogenicity of these products preclude large scale use and ethical questions remain unanswered, even within the context of research projects.