Researchers have confirmed the long-term benefits of adjuvant anastrozole to help stop recurrence of breast cancer in postmenopausal women with hormone-sensitive early breast cancer, according to a 10-year analysis of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial published in The Lancet Oncology (Nov 16, 2010. Epub ahead of print).
Using a proportional hazards model, the ATAC/LATTE investigators assessed disease-free survival, time to recurrence, time to distant recurrence, incidence of new contralateral breast cancer, overall survival, and death with or without recurrence after a median follow-up of 120 months. Data also was collected on fractures and serious adverse events.
The ATAC trial randomized patients to anastrozole (n = 3125) or tamoxifen (n = 3116). For the full study population (hormone sensitive–negative and –positive), disease-free survival improved for those in the anastrozole group compared with the tamoxifen group (HR, 0.91; 95% CI, 0.83-0.99; P = .04), as did time to recurrence (HR, 0.84; 94% CI, 0.75-0.93; P = .001), and time to distant recurrence (HR, 0.87; 95% CI, 0.77-0.99; P = .03). Analysis of hormone receptor–positive patients found improvement for those in the anastrozole group (n = 2618) over those in the tamoxifen group (n = 2598) for disease-free survival (HR, 0.86; 95% CI, 0.78-0.95; I = .003), time to recurrence (HR, 0.79; 95% CI, 0.70-0.89; P =·.0002), and time to distant recurrence (HR, 0.85; 0.73-0.98; P = .02).
Overall mortality was similar for both groups (HR, 0.95; 95% CI, 0.84-1.06; P = .4). Fractures were more frequent during therapy for those in the anastrozole group. Conversely, serious adverse events were fewer for those in the anastrozole group. Both fracture rates and serious adverse events were similar posttreatment completion.