Multicenter phase II trial of neoadjuvant exemestane for postmenopausal patients with hormone receptor-positive, operable breast cancer: Saitama Breast Cancer Clinical Study Group (SBCCSG-03)

Abstract

This multicenter phase II trial evaluated the efficacy and tolerability of 4 months of neoadjuvant exemestane in 44 postmenopausal patients with estrogen receptor (ER)-positive and/or progesterone receptor-positive, stage II to IIIB breast cancer measuring >or=3 cm. Pathological response was assessed by a central review board using response criteria proposed by the Japanese Breast Cancer Society. Clinical response [complete or partial response (PR)] was assessed by caliper, mammography, or ultrasound. Rates of breast-conserving surgery (BCS) and adverse events were also evaluated. A pathological response was observed in 13 (43%) of 30 patients who underwent surgery at 4 months. Fourteen patients were excluded from the pathological analysis: eight continued exemestane because of PR or stable disease (SD) at 4 months, three underwent chemotherapy because of progressive disease, and three underwent surgery within 2 months because of adverse events. A clinical response was seen in 27 (66%) of 41 evaluable patients. BCS was performed in 27 (90%) of 30 patients who underwent surgery at 4 months. Of the ten patients eligible for mastectomy at baseline, six chose to continue exemestane treatment without surgery because of a PR or SD at 4 months. Adverse events, most of which were grade 1, occurred in <or=10% of patients. These results suggest that neoadjuvant exemestane treatment is effective and well tolerated in postmenopausal women with ER-positive breast cancer. Further studies are required to determine the optimal duration of neoadjuvant treatment and to identify response criteria that can more accurately predict long-term outcomes.

Increased estrogen sulfatase (STS) and 17β-hydroxysteroid dehydrogenase type 1(17β-HSD1) following neoadjuvant aromatase inhibitor therapy in breast cancer patients

“…Several clinical studies have been reported using exemestane as primary endocrine therapy in operable breast cancer patients but results of clinical and pathological responses to exemestane varied among these studies [31][32][33][34]. Alterations in tumor histopathological features following aromatase inhibitors administration include the changes in cellularity, degree of fibrosis, histological grading [17,27], and treatment-related changes of cell proliferation, apoptosis, and hormone receptor expression were also described [31][32][33][34][35][36][37].…”

Early metabolic response to neoadjuvant letrozole, measured by FDG PET/CT, is correlated with a decrease in the Ki67 labeling index in patients with hormone receptor-positive primary breast cancer: a pilot study

“…Some clinical trials have shown that neoadjuvant endocrine therapy can contribute to down-staging and to improved therapeutic efficacy in HR-positive breast cancers [3][4][5]. Therefore, early identification of patients who do or do not respond to endocrine therapy is essential, allowing patients with less endocrinesensitive tumors to receive alternative treatments such as surgery or chemotherapy [6].…”

Neoadjuvant endocrine therapy for postmenopausal patients with hormone receptor-positive early breast cancer: a new concept

“…Several trials have assessed the efficacy and safety of neoadjuvant endocrine therapy using aromatase inhibitors in patients with postmenopausal breast cancer [20][21][22][23][24][25]. In a randomized phase II study in which neoadjuvant endocrine therapy and neoadjuvant chemotherapy were compared in patients with hormone receptor-positive breast cancer, no significant difference in the clinical response rate was observed between the two groups [26].…”