This chapter discusses both benign breast lesions and those that associated with an increased risk of breast cancer development, as well as the aetiology, clinical and pathologic prognosis, and hormonal treatment of breast cancers.
Clinical observations in women suggest that hormones play a role in the aetiology of benign lesions. In postmenopausal women receiving oestrogens (with or without progestins) for more than 8 years, the prevalence of benign breast lesions is increased 1.7-fold; whilst the anti-oestrogen, tamoxifen, is associated with a 28 % reduction in prevalence of benign breast lesions. Cyclic and non-cyclic breast pain, nipple discharge and breast lumps are all clinical features of benign breast lesions.
A practical classification, based primarily on degree of proliferation, distinguishes benign breast lesions with no associated increase in breast cancer risk from those with a small or moderate (i.e. 1.1–2.0- fold), or high risk (higher than 2.0-fold). Women considered at high risk of developing breast cancer can be treated with selective oestrogen receptor modulators (SERMS) including tamoxifen and raloxifene, which have been shown to decrease breast cancer risk by approximately 50 % when compared to placebo.
The aetiology of breast cancer includes the accumulation of mutations of key genes involved in cell proliferation, DNA repair, vasculogenesis, invasion, metastasis, and apoptosis; dietary, environmental, and lifestyle factors also play a key role. The majority of risk factors for breast cancer relate to the duration or intensity of a woman’s exposure to endogenous or exogenous oestrogens; mitogenic and mutagenic effects of oestradiol probably act in concert to initiate and promote the breast cancer development.
In this chapter, a variety of established and newer methods for classifying established breast cancers and predicting their prognosis and response to hormonal treatment strategies are discussed. The mechanisms (blockade of oestrogen synthesis or function) of hormonal treatments are described, as is the development of resistance to these treatments. An overview of the clinical efficacy of different hormonal treatments for breast cancer is given, as are recommended approaches to hormonal treatment of breast cancer in pre- and post-menopausal women, and in advanced disease states.
