Critical Appraisal of Primary Systemic Endocrine Therapy in Receptor-Positive Postmenopausal Breast Cancer: An Update

Abstract

Even in elderly patients, greater consideration is now being given to tumor volume reduction in locally advanced breast cancer, with increased subsequent breast-conserving surgery. Neoadjuvant endocrine therapy offers the possibility of testing therapeutic efficacy in vivo, which is of great importance for optimal adjuvant treatment. Resulting therapy modifications can be expected to increase disease-free as well as overall survival. Recent results indicate that remission rates with primary chemotherapy are significantly lower in receptor-positive than in receptor-negative breast cancer and that efficacy parameters in receptor-positive tumors tend to favor primary endocrine therapy, highlighting the increased importance of this type of treatment. Aromatase inhibitors are superior to tamoxifen in terms of clinical response as well as breast conservation rate. Results from a small number of studies suggest that prolonged preoperative aromatase inhibitor therapy for up to 12 months can increase the rate of clinical and pathological complete remissions. In conclusion, primary endocrine therapy is a valid therapeutic option for postmenopausal patients with locally advanced hormone receptor-positive breast cancer and significant comorbidity, increased risk of complications with regard to anesthesia and surgery, desire for breast-conserving surgery and/or reduced suitability for chemotherapy, as well as in very old patients.

The potential risk of neoadjuvant chemotherapy in breast cancer patients—results from a prospective randomized trial of the Austrian Breast and Colorectal Cancer Study Group (ABCSG-07)

“…Neoadjuvant endocrine therapy produces pCR rates ranging between 1 and 8% [20][21][22][23]. Hence, response rates achieved in our study are more likely to be compared to those achieved with preoperative endocrine therapy in hormone receptor-positive patients.…”

Antitumour and biological effects of letrozole and GnRH analogue as primary therapy in premenopausal women with ER and PgR positive locally advanced operable breast cancer

“…The value of pCR as surrogate end point of clinical outcome in ER-positive tumours after primary chemotherapy, which was called into question in former studies, was recently confirmed by the results of a large retrospective study showing that pCR was positively associated with outcome in both ER-negative and ER-positive tumours (Ring et al, 2004;Guarneri et al, 2006), but no data after primary endocrine therapy are available. A significantly increased response rate was reported with 6 months as compared with 3 months of preoperative letrozole therapy (Paepke et al, 2006). It may therefore be that a higher pCR rate might be observed with prolonged treatment in the preoperative setting.…”

Optimal Treatment Strategies in Hormone-Responsive Early Breast Cancer: The Role of Aromatase Inhibitors

“…Following results demonstrating that AIs are at least as effective as tamoxifen in the first-line treatment of locally advanced and metastatic breast cancer [10,11,13,34], their use was investigated in early disease in the neoadjuvant setting (table 1) [17][18][19][20][21]35]. Neoadjuvant therapy is given to shrink a tumor prior to surgery, and to increase the proportion of women who are eligible for breast-conserving surgery (BCS), and presents an ideal opportunity for assessment of the in vivo sensitivity of a tumor to systemic therapies.…”