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Bending the Curve Trial by Trial
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ATAC

Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: first results of the ATAC randomised trial

N = 9,366

Population
Postmenopausal women with invasive operable breast cancer who had completed primary therapy; 84% were known to be hormone-receptor-positive
Design
Randomised comparison of anastrozole, tamoxifen, or both for 5 years; efficacy analysed by intention to treat
Primary endpoint
DFS
Arms
  • Anastrozole (experimental, n = 3,125): Anastrozole 1 mg daily for 5 years
  • Tamoxifen (control, n = 3,116): Tamoxifen 20 mg daily for 5 years
  • Anastrozole plus tamoxifen (experimental, n = 3,125): Anastrozole plus tamoxifen for 5 years
People
Baum M, ATAC Trialists' Group
DFSHR 0.83 (95% CI 0.71–0.96)Δ 36-month DFS+2 pointsDFSHR 1.02 (95% CI 0.89–1.18)Δ 36-month DFS−0.2 pointsDFSHR 0.91 (95% CI 0.83–0.99)DFSHR 0.86 (95% CI 0.78–0.95)
Show the numbers
Results reported for ATAC
EndpointAnalysisAnastrozole / Anastrozole plus tamoxifenTamoxifenEffect
DFSprimarymedian follow-up 33.3 monthsBaum 200289.4% at 3 y87.4% at 3 yHR 0.83 (95% CI 0.71–0.96)P=0.013Improvement seen in the hormone-receptor-positive subgroup but not the receptor-negative subgroup (abstract).
DFSprimarymedian follow-up 33.3 monthsBaum 200287.2% at 3 y87.4% at 3 yHR 1.02 (95% CI 0.89–1.18)P=0.8
DFSlong term-updatemedian follow-up 120 monthsCuzick 2010——HR 0.91 (95% CI 0.83–0.99)P=0.04Median follow-up of 120 months; anastrozole n=3125, tamoxifen n=3116.
DFSHormone-receptor-positive patientslong term-updatemedian follow-up 120 monthsCuzick 2010——HR 0.86 (95% CI 0.78–0.95)P=0.003Anastrozole n=2618, tamoxifen n=2598 in this subgroup.
Results reported for ATAC
EndpointAnalysisAnastrozole / Anastrozole plus tamoxifenTamoxifenEffect
DFSprimarymedian follow-up 33.3 monthsBaum 200289.4% at 3 y87.4% at 3 yHR 0.83 (95% CI 0.71–0.96)P=0.013Improvement seen in the hormone-receptor-positive subgroup but not the receptor-negative subgroup (abstract).
DFSprimarymedian follow-up 33.3 monthsBaum 200287.2% at 3 y87.4% at 3 yHR 1.02 (95% CI 0.89–1.18)P=0.8
DFSlong term-updatemedian follow-up 120 monthsCuzick 2010——HR 0.91 (95% CI 0.83–0.99)P=0.04Median follow-up of 120 months; anastrozole n=3125, tamoxifen n=3116.
DFSHormone-receptor-positive patientslong term-updatemedian follow-up 120 monthsCuzick 2010——HR 0.86 (95% CI 0.78–0.95)P=0.003Anastrozole n=2618, tamoxifen n=2598 in this subgroup.
Hazard ratio (95% CI) by endpoint. Values below 1 favour the experimental arm.
DFSDFSDFSDFS0.512◀ experimentalcontrol ▶
Data table
EndpointHR95% CI
DFS0.830.71–0.96
DFS1.020.89–1.18
DFS0.910.83–0.99
DFS0.860.78–0.95
Primary publication: Baum M, Budzar AU, Cuzick J, Forbes J, Houghton JH, Klijn JG, et al. Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: first results of the ATAC randomised trial. Lancet. 2002;359(9324):2131-9. PubMedDOI

Appears in

Sources

  1. Baum M, Budzar AU, Cuzick J, Forbes J, Houghton JH, Klijn JG, et al. Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: first results of the ATAC randomised trial. Lancet. 2002;359(9324):2131-9.

    PubMedDOI

  2. Cuzick J, Sestak I, Baum M, Buzdar A, Howell A, Dowsett M, et al. Effect of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: 10-year analysis of the ATAC trial. Lancet Oncol. 2010;11(12):1135-41.

    PubMedDOI