sustaining a healthy lifestyle, and reducing susceptibility. One example of a change in individual behavior (by patients and physicians) that led to reduced breast cancer risk relates to the use of postmenopausal combined hormone therapy (HT). Although breast cancer incidence increased during the 1980s and 1990s, incidence data from 2002 to 2003 indicated a significant decline in breast cancer diagnosis in women in the United States.24 The most common explanation for this decline is the sharp drop in the use of HT after the 2002 publication of the Women’s Health Initiative findings that linked combined estrogen plus progestin HT with increased breast cancer risk.24 Medical interventions that reduce susceptibility to breast cancer include tamoxifen and raloxifene, both of which have been shown in clinical trials to be effective in reducing breast cancer among women at high risk for the disease.7 For women at extremely high risk of breast cancer, such as those with BRCA1 and BRCA2 genetic mutations, surgical interventions such as bilateral mastectomy (removal of both breasts) and/or oophorectomy (removal of ovaries)25, 26 substantially reduce breast cancer susceptibility. 2-6 Breast Cancer and the Environment: Prioritizing Prevention 2 potential interactions between genetic and environmental risk factors. The IOM also was asked to identify evidence-based actions that women could take to reduce their risk of breast cancer. Through its review of studies in humans, the IOM identified methodological challenges in conducting research on breast cancer and the environment and developed recommendations for future research. The recommendations emphasized the times during the life course when exposures might have the greatest impact on breast cancer. Major conclusions of the IOM report were the need for additional research on the causes of and ways to prevent breast cancer, and the difficulty in determining the contribution of many environmental factors to breast cancer risk.28 The IOM report is similar to this report in several aspects. Both reports include a broad definition of the environment. Both reports also provide an extensive literature review, along with recommendations that highlight research opportunities and descriptions of the challenges that hamper human studies of environmental exposures and breast cancer risk. The IOM report differs from this report in that the IOM committee was required by the sponsor to include recommendations about steps that individuals could take to reduce their breast cancer risk and to assess the standards by which recognized risk factors are measured. Unlike this report, the IOM report did not focus on the evaluation of the research process in government and nongovernmental organizations or include an examination of the dissemination and translation of research to the public. 2.5.2 President’s Cancer Panel The President’s Cancer Panel is required under the National Cancer Act of 1971 to regularly appraise the National Cancer Program. In 2009 and 2010, the Panel assessed the state of research, policy, and programs and focused on known and potential effects of environmental exposures on cancer. The Panel examined key regulatory, political, industrial, and cultural barriers to understanding and reducing environmental and occupational carcinogenic • approaches to stimulate and translate research on breast cancer and the environment. This report emphasizes the important roles of stakeholder groups and formulates strategies to engage these groups optimally in all research activities, from planning through knowledge integration and dissemination. 2.5 IBCERCC and Related Reports The IBCERCC and two other authoritative reports focus on the environment and breast cancer or all cancers. One report was developed by the Institute of Medicine (IOM)28 and the other, which focused on all cancers, was generated by the President’s Cancer Panel.b In developing the reports, all of the committees/panels had mechanisms for obtaining public input and comment. The IBCERCC held open meetings and published a request for input in the Federal Register. The IOM committee held a meeting at which the members could listen to concerns of advocates and community members; the President’s Cancer Panel held four town hall meetings in different regions of the United States in which anyone could participate. Whereas the IOM and President’s Cancer Panel reports focused on environmental influences on cancer, a third initiative, the National Conversation on Public Health and Chemical Exposures, addressed the effects of chemical exposures on environmental health more broadly. In that initiative, the CDC and the Agency for Toxic Substances and Disease Registry (ATSDR) engaged a broad range of stakeholders in the development of an action plan to protect the public from harmful chemicals.29 2.5.1 IOM Report The IOM was commissioned by the Susan G. Komen for the Cure Foundation to review the criteria for identifying and measuring cancer risk factors, the strength of the science regarding the relationship between breast cancer and the environment, and b Cancer and the Environment: Prioritizing Prevention 2 nation, involving more than 1,000 people. Through the