The complexity of the links between cancer and the environment, along with the challenges of prevention, call for an examination of public perceptions, attitudes, and concerns regarding this issue. This article aims to provide an overview of the public’s understanding of this topic and to examine the role of general practitioners in the information and prevention system. Methodology: The data used from the National Institute for Prevention and Health Education were derived from self-reported telephone surveys of representative random samples of the general population, on the one hand, and general practitioners, on the other. Results: In 2010, as in 2007, cancer was the disease most feared by the public. Beyond the well-established behavioral risks (tobacco, alcohol, and exposure to sunlight and artificial UV radiation), environmental concerns are on the rise, even though radon remains underestimated. Finally, there are high expectations for advice from general practitioners, even though they feel inadequately trained in environmental health. Conclusion: The opinion profiles identified among the public call for advances in prevention, scientific public information, the role of the media, and the training of healthcare professionals. [author’s abstract]