Anastrozole is superior to tamoxifen as first‐line therapy in hormone receptor positive advanced breast carcinoma

• Published in: Cancer Vol. 92; no. 9; pp. 2247 - 2258
• Main Authors: Bonneterre, Jacques, Buzdar, Aman, Nabholtz, Jean‐Marc A., Robertson, John F. R., Thürlimann, Bert, von Euler, Mikael, Sahmoud, Tarek, Webster, Alan, Steinberg, Mark
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.11.2001
• Subjects: Adult; Aged; Aged, 80 and over; Anastrozole; Antineoplastic Agents, Hormonal - pharmacology; aromatase inhibitor; breast carcinoma; Breast Neoplasms - drug therapy; Breast Neoplasms - pathology; Double-Blind Method; Female; Hemorrhage - chemically induced; hormone receptor; Humans; Middle Aged; Nitriles - pharmacology; postmenopausal; Postmenopause; Prognosis; Receptors, Estrogen - analysis; Receptors, Progesterone - analysis; Survival Analysis; tamoxifen; Tamoxifen - pharmacology; Thromboembolism - chemically induced; Treatment Outcome; Triazoles - pharmacology
• ISSN: 0008-543X; 1097-0142
• DOI: 10.1002/1097-0142(20011101)92:9<2247::AID-CNCR1570>3.0.CO;2-Y

BACKGROUND Two randomized, double‐blind trials have compared tamoxifen 20 mg daily and the selective, nonsteroidal aromatase inhibitor anastrozole 1 mg daily as first‐line therapy for advanced breast carcinoma (ABC) in postmenopausal women. The trials were prospectively designed to allow for combined data analyses. METHODS The combined study population included 1021 postmenopausal women (median age, 67 years [range, 30–92]) with ABC whose tumors were either estrogen and/or progesterone receptor positive or of unknown receptor status. Primary endpoints were time to progression (TTP), objective response, and tolerability. RESULTS At a median duration of follow‐up of 18.2 months, anastrozole was at least equivalent to tamoxifen in terms of median TTP (8.5 and 7.0 months, respectively; estimated hazard ratio [tamoxifen relative to anastrozole], 1.13 [lower 95% confidence level, 1.00]). In a retrospective subgroup analysis, anastrozole was superior to tamoxifen with respect to TTP (median values of 10.7 and 6.4 months for anastrozole and tamoxifen, respectively, two‐sided P = 0.022) in patients with estrogen and/or progesterone receptor positive tumors (60% of combined trial population). In terms of objective response, 29.0% of anastrozole and 27.1% of tamoxifen patients achieved either a complete response (CR) or a partial response (PR). Clinical benefit (CR + PR + stabilization of ≥ 24 weeks) rates were 57.1% and 52.0% for anastrozole and tamoxifen, respectively. Both anastrozole and tamoxifen were well tolerated. Anastrozole led to significantly fewer venous thromboembolic (P = 0.043; not adjusted for multiple comparisons) events, and vaginal bleeding was reported in fewer patients treated with anastrozole than with tamoxifen. CONCLUSIONS In postmenopausal women with hormonally sensitive ABC, anastrozole should be considered as the new standard first‐line treatment. Cancer 2001;92:2247–58. © 2001 American Cancer Society. In this comparison of two large multicenter studies, involving 1021 patients, the authors found that anastrozole was at least as effective as tamoxifen for the first‐line treatment of advanced breast carcinoma in postmenopausal women whose tumors were either receptor positive or of unknown receptor status. They conclude that anastrozole should be considered as the new standard first‐line therapy for postmenopausal women with receptor‐positive or receptor‐unknown advanced breast carcinoma.