A large body of information about possible causes of cancer has been ac cumulated by both clinical experience in man and observations in animal experiments. There is general agreement that in most cases cancer is due to exogenous factors, albeit the genetic disposition may also play an impor tant part. Three main categories of exogenous risk factors have been iden tified, namely chemicals, radiation, and viruses. In principle, it should be possible to prevent cancer by eliminating such risk factors. However, in spite of the rapidly growing number of well established risk factors, many shortcomings in our understanding of the causes of human cancer and in the introduction of effective preventive measures are evident. In addition to obvious gaps in our scientific knowledge, inadequacies in personal life style, irresponsible handling of environmental contaminants, and in some areas also deficiencies in political decisions seriously hamper the elimina tion of risk factors for cancer. It was this background which prompted the Committee coordinating Cancer Research in the GroBforschungseinrichtungen in the Federal Re public of Germany to organize a conference on Strategies for the Elimina tion of Cancer Risks. The conference was held in Heidelberg in June 1986. In areas which appeared to be especially pertinent to public health, author itative speakers presented the state of the art and prepared the basis for the discussion. Both the presentations of the speakers and the summaries of the discussions are contained in this book.

Session 1 General Aspects

Genetic Predisposition for Cancer Risks in Man
The Role of Epidemiology in the Detection and Reduction of Cancer Risks
Session 2 Chemical Carcinogens: Risk Assessment
Assessment of Cancer Risk from Chemicals
Validity of Short-Term Tests to Detect Carcinogenic Chemicals (With 5 Figures)
Preneoplastic Lesions as Indicators of the Carcinogenic Risk Caused by Chemicals (With 6 Figures)
Carcinogenic Risk Assessment: Are Animals Good Surrogates for Man?
Session 3 Chemical Carcinogens: Primary Prevention
Possibilities of Primary Prevention Against Chemical Carcinogens (With 3 Figures)
Primary Prevention Against Occupational Carcinogens
Chemical Carcinogens in Tobacco (With 4 Figures)
Primary Prevention of Tobacco-Related Cancer (With 6 Figures)
Session 4 Physical Carcinogens
Cancer Risk from Ultraviolet Radiation
Assessment of Cancer Risks Due to Ionizing Radiations (With 1 Figure)
Cancer Risk from Environmental Radioactivity (With 5 Figures)
Session 5 Oncogenic Viruses
Viruses in Human Tumors (With 1 Figure)
Strategies in the Prevention of Infections by Oncogenic Viruses (With 3 Figures)
Summary of Round Table Discussion on Strategies Against Tobacco Cancer.