Breast cancer prevention

Early detection, combined with targeted and more effective therapies, has led to reductions in breast cancer related deaths. Approximately 90% of women diagnosed with breast cancer in the US today are disease free 5 years after diagnosis. Despite these successes, breast cancer remains a major cause of death, particularly among young women. In addition, chronic or prolonged toxicities associated with cancer treatments contribute to overall morbidity and reduced quality of life for more than two million breast cancer survivors in the US alone. Increasing rates of breast cancer worldwide, especially among previously low-risk regions and low-risk populations, are creating new concerns (Minami et al. 2004; Althuis et al. 2005; Bosetti et al. 2005). This is a particularly worrisome trend for regions and populations where use of screening and access to targeted therapies are limited. Given the worldwide burden of breast cancer in terms of lives impacted (nearly 1.3 million new cases per year) and lives lost annually (estimated 464,854 annual deaths), prevention of invasive breast cancers remains a major global public health priority (Garcia et al. 2007). In this chapter we update information on breast cancer etiology and changing patterns of disease incidence by race and age with a focus on female breast cancers. Male breast cancer is rare and distinct from breast cancers that occur among women and are discussed elsewhere (Dimitrov et al. 2007; Tai et al. 2007). This chapter details current information on risk factors, emphasizing their contribution to risk assessment tools and clinically useful definitions of high risk for patient counseling. We address race and breast cancer with a focus on what the physician needs to know about screening and risk assessment in specific populations. For example, the status on the efficacy of available genetic testing for familial forms of the disease and risk assessment tools are described as they apply to African American, Asian and Hispanic women. This chapter concludes with a discussion of current thinking regarding the role of prevention strategies for women at low, moderate and high risk for breast cancer, with special focus on current recommendations for the use of the selective estrogen receptor (ER) modulators or SERMs (e.g., tamoxifen, raloxifene) for the primary prevention of disease in women at high risk.