This is a prospective, non-comparative, non interventional study (NIS) in four hundred (400) postmenopausal women hormone-receptor positive invasive with early breast cancer, following 2-3 years of initial adjuvant tamoxifen therapy conducted in 60 sites from Romania according to protocol A5991091.The selection of patients based on diagnosis, the attribution of medicinal products and the follow-up of the subjects fall within the current medical practice. A Non-Interventional study is primarily observational in nature. The present Non-interventional Study is performed by medical oncologist and medical oncologist /radiation oncologist who agree to take part in this project. n/a The study was prematurely terminated on August 31th 2012 due to unexpected high rate of patient withdrawal caused by Aromasin reimbursement policy change in Romania; There were no safety issues related to study termination.