Anastrozole bests tamoxifen as adjuvant treatment for early-stage breast cancer

In postmenopausal women with early-stage breast cancer, anastrozole is superior to tamoxifen for adjuvant treatment, according to a report in the November 1st issue of Cancer.

Earlier results from the ATAC (Arimidex, Tamoxifen Alone or in Combination) trial showed prolonged disease-free survival and time to recurrence in patients receiving anastrozole alone compared with those receiving tamoxifen alone or in combination with anastrozole, the authors explain.The ATAC Trialists’ Group assessed disease-free survival, time to recurrence, safety, and other measures in the same patient group as in the first analysis of the ATAC trial, based on a median follow-up period of 47 months. The earlier survival results were based on a median follow-up of 33 months.Disease-free survival continued to be significantly longer with anastrozole treatment (86.9%) than with tamoxifen treatment (84.5%), the authors report, both overall and even more significantly among patients with hormone receptor-positive breast cancer.Time to recurrence was also superior for patients receiving anastrozole than for those receiving tamoxifen, the report indicates, especially among women with hormone receptor-positive tumors.Women receiving anastrozole were less than two-thirds as likely as women receiving tamoxifen to develop contralateral breast cancer, the researchers note.Anastrozole continued to show a safety profile superior to that of tamoxifen, the results indicate, causing fewer hot flashes, less vaginal bleeding and discharge, and a lower incidence of endometrial malignancies, ischemic cerebrovascular events, and venous thromboembolic events.”These updates confirm the value of anastrozole in this setting and provide additional support for the use of anastrozole as adjuvant therapy for postmenopausal women with hormone-sensitive early-stage breast cancer,” the authors conclude.”It appears likely that some variant of an adjuvant regimen containing aromatase inhibitors eventually will prove to be superior to single-agent tamoxifen for at least some patients with breast malignancies,” writes Dr. Gini F. Fleming from The University of Chicago Hospitals and Health System, Chicago, Illinois in a related editorial.”Meanwhile, however,” Dr. Fleming concludes, “given the long natural history of this disease and the uncertainties regarding the duration of the effects of anastrozole, the opinion of the ASCO Technology Assessment Working Group is reasonable: a change in the standard of care is not yet indicated.”(Source: Cancer 2003;98:1802-1810,1779-1781: Reuters Health: November 27, 2003: Oncolink)