Treatment of established breast cancer in post-menopausal women: Role of aromatase inhibitors

Endocrine therapy plays a crucial and historically important role in the treatment ofwomen with hormone-responsive breast cancer. Tamoxifen has been the standard endocrine treatment for advanced and early-stage breast cancer for almost three decades. However, patients receiving tamoxifen may either fail to respond or develop disease recurrence following completion of therapy. The aromatase inhibitors (Als) have become the new and alternative modalities of endocrine treatment for post-menopausal women with oestrogen receptor-positive breast cancer, as a result of promising data from randomised trials in metastatic and locally advanced breast cancers. Recently, the results from several large, randomised, controlled adjuvant trials have provided further evidence that the use of Als, either as initial treatment or sequentially after tamoxifen, improves disease-free survival and, in certain patients, overall survival. With relatively short-term follow-up, the use of Als has been shown to be safe and welltolerated. Nevertheless, some detrimental adverse effects, particularly skeletal-related events or cardiovascular disease, remain important issues of concern and warrant continued monitoring and follow-up. The optimal use of Als, the appropriate timing of treatment, and the superiority of individual agents are under investigation. Use of Als in women with chemotherapy-induced amenorrhoea should be cautious due to the possibility of return of ovarian function. Cost-effectiveness and quality of life remain issues of interest since the high and ever increasing incidence of breast cancer has contributed to significant healthcare costs and patients with breast cancer following appropriate treatment are living longer but not necessarily being cured of their diseases.