Women who have taken tamoxifen for 2 years as adjuvant chemotherapy for breast cancer may receive greater clinical benefit if they switch to anastrozole rather than continuing with tamoxifen, researchers report in the July 1 issue of the 

Manfred Kaufmann, MD, from the J.W. Goethe-University of Frankfurt in Germany, and others randomly assigned 979 patients receiving tamoxifen for 2 years to anastrozole at 1 mg/day for an additional 3 years or to a full 5-year course of tamoxifen to compare the disease-free survival rates. Overall survival and safety were also measured. 

The investigators found that switching to anastrozole reduced the risk of disease recurrence (hazard ratio, 0.66) and improved overall survival (HR, 0.53). More side effects were apparent in the continued tamoxifen group, largely due to endometrial events. 

The study was supported by a grant from AstraZeneca and some of the authors report receiving consulting fees, honoraria or grants from AstraZeneca, Pfizer and/or Novartis. 

Kaufmann M, Jonat W, Hilfrich J, et al. Improved overall survival in postmenopausal women with early breast cancer after anastrozole initiated after treatment with tamoxifen compared with continued tamoxifen: The ARNO 95 Study. 

Women who have taken tamoxifen for 2 years as adjuvant chemotherapy for breast cancer may receive greater clinical benefit if they switch to anastrozole rather than continuing with tamoxifen, researchers report in the July 1 issue of the Journal of Clinical Oncology.