Bonneterre J, Thurlimann B, Robertson JFR, Krzakowski M, Mauriac L, Koralewski P, Vergote I, Webster A, Steinberg M, and von Euler M for the Arimidex Study Group. Anastrozole is a selective nonsteroidal aromatase inhibitor which gives near maximal estrogen suppression in the peripheral circulation and within the tumor. Tamoxifen is a mixed agonist antagonist of estrogen. The studies argue that anastrozole can be considered first line treatment for postmenopausal women with advanced breast cancer. Compared to tamoxifen, anastrozole had a lower rate of thromboembolic events and vaginal bleeding, and in one study a longer time to progression of disease.
Tamoxifen has an extensive, proven record.
Overall, rates of depression and asthenia were not significantly different for the two drugs. While these were not systematic psychiatric assessments, these studies do not suggest a major increase in affective symptoms with anastrozole.