Role of aromatase inhibitors in the upfront adjuvant hormonal therapy of postmenopausal patients with breast cancer.

Tamoxifen has been considered for several decades as the standard upfront hormonal therapy for patients with endocrine-sensitive early breast cancer. The efficacy and favorable toxicity profiles of third-generation aromatase inhibitors (AIs), anastrozole, letrozole and exemestane, in advanced disease led to their development in early breast cancer. Recent trial results consistently showed the superiority of AIs over tamoxifen in using the two following therapeutic approaches: either the upfront strategy (randomization of newly diagnosed patients: tamoxifen for 5 years vu AI for 5 years) or the sequencial strategy (randomization of newly diagnosed patients: tamoxifen (2-3 years) followed by AI or the inverse for a total of 5 years vs upfront AI for 5 years).Despite some common characteristics, a body of evidence on AIs suggests some specific differences between the three agents in terms of efficacy as well as toxicity profiles. Thus, these hormonal agents may not be considered interchangeable in clinical practice. This review will explore available results from AIs trials and will try to define their present role in the upfront adjuvant management of postmenopausal patients with breast cancer.

Role of neo-adjuvant hormonal therapy in the treatment of breast cancer: a review of clinical trials.

The clinical benefits of endocrine therapy for patients with hormonosensitive breast cancer are well established. For many years, 5 years of tamoxifen was the gold standard of adjuvant treatment. The recent development of new endocrine agents provides physicians with a more effective therapeutic approach. Nevertheless, the success of neoadjuvant endocrine therapy is much more recent and less reported in the literature. This article reviews the studies published about neoadjuvant endocrine treatment (tamoxifen and aromatase inhibitors). According to the literature, neoadjuvant endocrine therapy seems to be effective. In contrast to neoadjuvant chemotherapy, neoadjuvant endocrine therapy is well tolerated, with very few patients having to discontinue the treatment because of side effects. It does not constitute a standard treatment but could have potential for elderly women with operable, hormonosensitive, well differentiated and slowly progressing (SBR I) tumor or for patients with lobular MSBR 1 carcinoma (low chemosensitivity). The newer generation of aromatase inhibitors (letrozole, anastrozole, exemestane) appears to be more active (in terms of overall response rates and conservative surgery rate) than tamoxifen. Patients with an estrogen receptor Allred score of 6 and over are more likely to respond and gain a clinical benefit. The optimal duration of neoadjuvant therapy has not yet been investigated in detail. These preliminary results should be confirmed by further studies.