Prediction, Communication, and Distribution of Breast Cancer Risk

Thesis (Ph.D.)--University of Washington, 2012Hispanic women represent the only racial/ethnic group in the United States (US) for which breast cancer is the most frequently diagnosed cancer and leading cause of cancer deaths. Despite the availability of tools to assess breast cancer risk, relatively little is known about the performance of current breast cancer risk prediction models and distribution of breast cancer risk in Hispanic women. Furthermore, there is limited evidence on the utility of decision aids designed to help women at high risk for breast cancer make informed choices about chemoprevention. To address these gaps, the overall goal of the proposed research work was threefold: 1) evaluate breast cancer risk projections for Hispanic women; 2) assess the distribution of breast cancer risk among Hispanic women; and 3) assess the impact of a web-based, tailored decision aid for women at high risk for breast cancer. We used data from two nationally representative datasets with information on US Hispanic women, and a randomized trial of women at high risk of breast cancer. Statistical analyses included multivariate linear, logistic, and Cox regression techniques. Findings from this work contribute valuable information on the use of estimates of breast cancer risk in research, clinical practice and public health. First, the National Cancer Institute's Breast Cancer Risk Assessment Tool (BCRAT), the most widely used breast cancer risk prediction model, underestimates risk of developing invasive breast cancer in US Hispanic women. Second, the risk of developing invasive breast among Hispanic women, based on the BCRAT, is significantly lower compared to non-Hispanic white women, though breast cancer risk also significantly differs between certain Hispanic subgroups. Third, personalized decision aids may be effective tools to provide useful information about women's risk of developing specific types of breast cancer, as well as to facilitate informed medical decisions, reduce patients' decisional conflict, and empower patients to choose a treatment strategy that best reflects their own values. Together, these results improve our understanding of the prediction and distribution of breast cancer risk among US Hispanic women, and help identify ways in which breast cancer risk can be communicated to help inform women about their treatment options