Facilitating Breast-Conserving Surgery and Preventing Recurrence: Aromatase Inhibitors in the Neoadjuvant and Adjuvant Settings

Breast-conserving surgery (BCS) is an attractive option for many patients with early-stage breast cancer, because it provides a better cosmetic outcome than modified radical mastectomy, while reducing surgical morbidity. In patients with large, operable breast tumors who are ineligible for BCS, neoadjuvant therapy is a useful option for reducing the tumor size and for increasing the proportion of candidates for BCS. In patients with endocrine-responsive tumors, neoadjuvant endocrine therapy with either tamoxifen or an aromatase inhibitor (AI; anastrozole, letrozole, or exemestane) provides an alternative to neoadjuvant chemotherapy. Clinical trials have demonstrated the superiority of neoadjuvant AIs over tamoxifen in achieving a clinical response and increasing the frequency of BCS. In addition, adjuvant endocrine therapy with AIs, whether used as initial therapy instead of tamoxifen, in a switching strategy after 2–3 years of tamoxifen, or as extended adjuvant therapy after 5 years of adjuvant tamoxifen, has been shown in several randomized clinical trials to improve disease-free survival, reduce distant metastases and, in some cases, improve overall survival. The availability of the AIs for effective and well-tolerated neoadjuvant and/or adjuvant endocrine therapy represents an important advance in breast cancer treatment, and surgeons should be familiar with these new therapeutic options.