ABSTRACT
Globally, breast cancer is the most frequently diagnosed cancer among women, with an estimated 1.38 million new cancer cases diagnosed in 2008, and is the leading cause of cancer death in women. Family history identifies a minority of patients at increased lifetime risk of breast cancer due to a mixture of shared environmental and genetic factors. Somatic mutation theory postulates the accumulation of mutations in genes that progressively deregulate normal breast cell behaviour as the cause of breast cancer. Invasive breast carcinomas consist of several histological subtypes; invasive ductal carcinoma accounts for 75%, invasive lobular carcinoma accounts for 8%–10% and medullary carcinoma accounts for 1%–2% of all invasive breast cancers. For postmenopausal women with oestrogen receptor (ER)-positive breast cancer, neoadjuvant endocrine treatment has been proposed as an appropriate approach after its established efficacy in the adjuvant setting and the increasing recognition that chemotherapy may be less effective in ER-positive human epidermal growth factor receptor 2-negative disease.
