First report of the European Cooperative Trial in Operable Breast Cancer II (ECTO II): Effects of primary chemo-endocrine therapy on local-regional disease in ER-positive breast cancer

Abstract

588 Background: To improve the pathologic complete remission rate documented in the ECTO trial (ASCO 2002), in June 2005 we activated a randomized phase II two stage-type protocol with concomitant chemo-endocrine therapy in ER-positive breast cancer > 2 cm at diagnosis. Methods: 182 patients were enrolled by end of June 2007. Patients were randomly allocated to 3 chemotherapy regimens: A (AT, doxo 60 mg/m2 + paclitaxel 200 mg/m2, q 3 w x 4 followed by CMF d1+8 q 4 w x 4); B (AT as above followed by CM d1+8 + capecitabine 1,850 mg/m2 for 14 days q 4 w x 4); C (AC, doxo 60 mg/m2 + cyclophosphamide 600 mg/m2 q 3 w x 4 followed by paclitaxel 100 mg/m2 d1+8 + capecitabine as above q 3 w x 4). Exemestane (25 mg/day) was given from the start of chemotherapy till surgery in all 3 regimens, along with LH-RH analogues in all premenopausal women. Results: At the cut-off date of August 31, 2007, 102 patients were assessed for the first step of the analysis plan. Baseline characteristics (age, menopause, PgR and HER2) were well balanced and left ventricular ejection fraction (LVEF) was similar in all 3 groups. Treatment was fairly well tolerated, but more frequently delayed in arms B and C. Median delivered doses of all drugs were similar in all 3 regimens. Grade 3 neutropenia was more frequently observed during AC (7%) than during AT (3%), while no episodes of thrombocytopenia were documented. CTC 3 LVEF modification was documented in one patient in arm C. Rates of complete pathologic absence of invasive cancer in the breast (pCR) and in the breast and axilla (tnpCR) are reported in the Table. Conclusions: Exemestane did not appear to add on the expected pCR rate by chemotherapy in ER-positive cases. The capecitabine-containing regimens were more active than the non-capecitabine one. Regimen A Regimen B Regimen C Patients (n°) 35 32 35 % pCR 5.7 (0.7 - 19.2) 15.6 (5.3 - 32.8) 8.6 (1.8 -23.1) % tnpCR 2.9 (0.1 - 14.9) 12.5 (3.6 - 29.0) 8.6 (1.8 -23.1) 95% confidence limits Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Roche Roche