SBCCSG-03 EBCC abstract
Multicenter phase II trial of neoadjuvant exemestane for postmenopausal patients with hormone-sensitive, operable breast cancer: Saitama Breast Cancer Clinical Study Group (SBCCSG-03)Hiroyuki Takei, Kimito Suemasu, Kenichi Inoue, Tsuyoshi Saito, Katsuhiko Okubo, Junichi Koh, Kazuhiko Sato, Hitoshi Tsuda, Masafumi Kurosumi, Toshio Tabei 5th European Breast Cancer Conference, 21-25 March,2006
Background: Randomized trials have shown that neoadjuvant letrozole and anastrozole can reduce tumor volume, allowing breast-conserving surgery (BCS) rather than mastectomy for operable tumors. Type I anti-aromatase agent exemestane (EXE) is also promising, however; its use for neoadjuvant therapy has not been reported. Purpose: Multicenter phase II trial (SBCCSG-03) was designed to evaluate the efficacy and tolerability of neoadjuvant EXE for postmenopausal patients (pts) with estrogen receptor (ER) and/or progesterone receptor (PR) positive breast cancer. Patients and Methods: Postmenopausal pts with ER and/or PR positive, stage II to IIIB and 3 cm or larger-sized operable breast cancer were assigned to neoadjuvant EXE (25 mg daily) for 4 months and followed by surgery. The pathological response defined as grade 1b, 2 or 3 was assessed by a central review according to "General Rules for Clinical and Pathological Recording of Breast Cancer 2005" published by The Japanese Breast Cancer Society. The clinical response defined as complete (CR) or partial (PR) response was assessed by caliper, mammography, or ultrasound. BCS rate and adverse events were also evaluated. Results: Forty-four pts were enrolled and all of them were eligible. The median age was 60 years (range, 48-88). Stage IIA, IIB, IIIA and IIIB were the disease of 26, 8, 4 and 6 pts, respectively. ER and PR positive tumor was in 32 pts, and ER positive and PR negative tumor was in 12 pts. Of 44 eligible pts, three discontinued 4-months EXE due to hematological disorder (grade 3), dizziness (grade 2) or genital bleeding (grade 1), and underwent surgery. There were a few other adverse events, most of which were grade 1. In 41 pts, CR and PR were found in 0 and 27 pts, respectively; clinical response rate was 66%. Stable disease (SD) and progressive disease (PD) were found in 9 (22%) and 5 (12%), respectively. Three pts underwent chemotherapy because of PD. Eight pts refused surgery due to PR or SD after 4-months EXE, and continued EXE. The pathological response was obtained in 13 (43%) of 30 pts who underwent surgery after 4-months EXE; grade 1b in 9 and grade 2 in 4 pts. BCS was performed in 28 pts (93%). Conclusion: Neoadjuvant EXE is effective and well tolerated in hormone-sensitive, operable breast cancer in postmenopausal pts.