Dubsky PC, Jakesz R, Mlineritsch B, Pöstlberger S, Samonigg H, Kwasny W, Tausch C, Stöger H, Haider K, Fitzal F, Singer CF, Stierer M, Sevelda P, Luschin-Ebengreuth G, Taucher S, Rudas M, Bartsch R, Steger GG, Greil R, Filipcic L, Gnant M. Tamoxifen and anastrozole as a sequencing strategy: a randomized controlled trial in postmenopausal patients with endocrine-responsive early breast cancer from the Austrian Breast and Colorectal Cancer Study Group.
J Clin Oncol 2012;
30:722-8. [PMID:
22271481 DOI:
10.1200/jco.2011.36.8993]
[Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE
Anastrozole (ANA) alone delivers significant disease-free survival benefits over tamoxifen (TAM) monotherapy in postmenopausal women with early estrogen receptor-positive breast cancer. The ABCSG-8 (Austrian Breast and Colorectal Cancer Study Group 8) study is a large phase III clinical trial addressing the sequence strategy containing ANA in comparison with 5 years of TAM in a low- to intermediate-risk group of postmenopausal patients.
PATIENTS AND METHODS
Endocrine receptor-positive patients with G1 or G2 tumors were eligible. After surgery, patients were randomly assigned to 5 years of TAM or 2 years of TAM followed by 3 years of ANA. Adjuvant chemotherapy and G3 and T4 tumors were exclusion criteria. Intention-to-treat and censored analyses of on-treatment recurrence-free survival (RFS) were performed, and exploratory survival end points and toxicity were investigated.
RESULTS
Information from 3,714 patients, including 17,563 woman-years, with a median of 60 months of follow-up was available for this analysis. Median age was 63.8 years, 75% were node negative, and 75% had T1 tumors. Sequencing of ANA after identical 2-year treatment with TAM in both arms did not result in a statistically significant improvement of RFS (hazard ratio [HR], 0.80; 95% CI, 0.63 to 1.01; P = .06). Exploratory analyses of distant relapse-free survival indicated a 22% improvement (HR, 0.78; 95% CI, 0.60 to 1.00). On-treatment adverse events and serious adverse events were consistent with known toxicity profiles of ANA and TAM treatment.
CONCLUSION
Despite a low overall rate of recurrence in a population with breast cancer at limited risk of relapse, the a priori sequence strategy of 2 years of TAM followed by 3 years of ANA led to small outcome and toxicity benefits.
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