Ethical issues in cancer screening and prevention.

November 2009's announcement of the USPSTF's recommendations for screening for breast cancer raised a firestorm of objections. Chief among them were that the panel had insufficiently valued patients' lives or allowed cost considerations to influence recommendations. The publicity about the recommendations, however, often either simplified the actual content of the recommendations or bypassed significant methodological issues, which a philosophical examination of both the science behind screening recommendations and their import reveals. In this article, I discuss two of the leading ethical considerations at issue in screening recommendations: respect for patient autonomy and beneficence and then turn to the most significant methodological issues raised by cancer screening: the potential biases that may infect a trial of screening effectiveness, the problem of base rates in communicating risk, and the trade-offs involved in a judgment of screening effectiveness. These issues reach more broadly, into the use of "evidence-based" medicine generally, and have important implications for informed consent.