Switching to anastrozole after tamoxifen improves survival in postmenopausal women with breast cancer
design and interventiOn This prospective, randomized, open-­label trial recruited postmenopausal women (age ≤70 years) with histologically verified grade 1–3 invasive breast cancer who had undergone primary surgery (with or without radiotherapy) and had received 2 years of continuous tamoxifen therapy (20 or 30 mg/day) between December 1996 and August 2002. Patients were randomly allocated to either treatment with anastrozole, (1 mg/day) or continu-­ ation of tamoxifen therapy (20 or 30 mg/day), for 3 years. Patients were monitored for disease recurrence and adverse events every 6 months for 3 years and every 12 months thereafter.