Ethical issues: changing attitudes and practices.

Ethical questions about the conduct of cancer prevention research need to be addressed at individual, organizational, community, and national levels. These questions have been highlighted by the demands of women and minorities to be included in research, the participation of practicing clinicians in prevention research, the lack of consensus about the nature of the contract between participants and investigators, the locus of liability for public health interventions, the degree of safety needed for preventive interventions, the relative certainty needed to classify participants at high enough relative risk to be exposed to toxic or potentially toxic agents. A number of ongoing chemoprevention and behavioral intervention U.S. trials are used to illustrate these issues. A question will also be raised about the extent to which future preventive programs are determined by current decisions about priorities for research funding and whether these priorities match national needs and public preferences.