Anastrozole is superior to tamoxifen as first-line therapy in hormone receptor positive advanced breast carcinoma - Results of two randomized trials designed for combined analysis
J. Bonneterre et al., Anastrozole is superior to tamoxifen as first-line therapy in hormone receptor positive advanced breast carcinoma - Results of two randomized trials designed for combined analysis, CANCER, 92(9), 2001, pp. 2247-2258
BACKGROUND. Two randomized, double-blind trials have compared tamoxifen 20
mg daily and the selective, nonsteroidal aromatase inhibitor anastrozole I
mg daily as first-line therapy for advanced breast carcinoma (ABC) in postm
enopausal women. The trials were prospectively designed to allow for combin
ed data analyses.
METHODS. The combined study population included 1021 postmenopausal women (
median age, 67 years [range, 30-92]) with ABC whose tumors were either estr
ogen and/or progesterone receptor positive or of unknown receptor status. P
rimary endpoints were time to progression (TTP), objective response, and to
lerability.
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 anal
ysis, anastrozole was superior to tamoxifen with respect to TTP (median val
ues 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 po
sitive tumors (60% of combined trial population). In terms of objective res
ponse, 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 greater than or equal to 24 weeks) rates were 57.1%
and 52.0% for anastrozole and tamoxifen, respectively. Both anastrozole an
d tamoxifen were well tolerated. Anastrozole led to significantly fewer ven
ous thromboembolic (P = 0.043; not adjusted for multiple comparisons) event
s, and vaginal bleeding was reported in fewer patients treated with anastro
zole than with tamoxifen.
CONCLUSIONS. in postmenopausal women with hormonally sensitive ABC, anastro
zole should be considered as the new standard first-line treatment. (C) 200
1 American Cancer Society.