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Comparative Study
. 2005 Jan 1-7;365(9453):60-2.
doi: 10.1016/S0140-6736(04)17666-6.

Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) Trial After Completion of 5 Years' Adjuvant Treatment for Breast Cancer

Affiliations
Comparative Study

Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) Trial After Completion of 5 Years' Adjuvant Treatment for Breast Cancer

A Howell et al. Lancet. .

Abstract

The standard adjuvant endocrine treatment for postmenopausal women with hormone-receptor-positive localised breast cancer is 5 years of tamoxifen, but recurrences and side-effects restrict its usefulness. The aromatase inhibitor anastrozole was compared with tamoxifen for 5 years in 9366 postmenopausal women with localised breast cancer. After a median follow-up of 68 months, anastrozole significantly prolonged disease-free survival (575 events with anastrozole vs 651 with tamoxifen, hazard ratio 0.87, 95% CI 0.78-0.97, p=0.01) and time-to-recurrence (402 vs 498, 0.79, 0.70-0.90, p=0.0005), and significantly reduced distant metastases (324 vs 375, 0.86, 0.74-0.99, p=0.04) and contralateral breast cancers (35 vs 59, 42% reduction, 12-62, p=0.01). Almost all patients have completed their scheduled treatment, and fewer withdrawals occurred with anastrozole than with tamoxifen. Anastrozole was also associated with fewer side-effects than tamoxifen, especially gynaecological problems and vascular events, but arthralgia and fractures were increased. Anastrozole should be the preferred initial treatment for postmenopausal women with localised hormone-receptor-positive breast cancer.

Comment in

  • ATAC trial update.
    Del Mastro L, Venturini M. Del Mastro L, et al. Lancet. 2005 Apr 2-8;365(9466):1225; author reply 1225-6. doi: 10.1016/S0140-6736(05)74802-9. Lancet. 2005. PMID: 15811447 No abstract available.
  • ATAC trial update.
    de Castro G Jr. de Castro G Jr. Lancet. 2005 Apr 2-8;365(9466):1225; author reply 1225-6. doi: 10.1016/S0140-6736(05)74801-7. Lancet. 2005. PMID: 15811448 No abstract available.

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