I have just read the supplement reporting the proceedings of the September 1992 American Cancer Society National Conference on Cancer Prevention and Early Detection. This is a timely and valuable addition to the literature.
I am concerned, however, about the content of the conclusion of Bal and Foerster's article.' They state that, with resources dedicated to dietary modification in the general population, there would be potential savings of 300,000 new cancer cases, 160,000 deaths, and $25 billion in associated costs.
Current scientific evidence simply does not support this clearly inflated and overoptimistic estimate of the capability of dietary modification to influence cancer risk. Promulgation of unrealistic expectations from any intervention results in skepticism in the populations being approached and loss of confidence in the "authorities" who make the intervention recommendations. 1 would hope that the American Cancer Society will not base diet recommendations on uncritical estimates of risk reduction or on current policy statements, but will define sound advice based solely on hard, scientifically reliable clinical data. This may result in very soft recommendations. If so, perhaps strengthening the links between groups working with dietary change to affect other risks such as cardiovascular disease would be valuable. I remember an aphorism from my teacher and colleague Kenneth B. Olson, M.D. "To be positive is to be wrong in a loud voice!" Let's be more careful and conservative about what we say about diet and cancer prevention.