This clinical trial is focused on studying the treatment of breast cancer, which is the most common cancer among women in North America, Europe, and Latin America. The study involves post-menopausal women with early-stage breast cancer that responds to hormones. The trial is comparing two different ways of giving treatment: giving chemotherapy and aromatase inhibitors at the same time (concurrent) versus one after the other (sequential). Aromatase inhibitors are medications that help lower estrogen levels in the body, which can slow the growth of certain types of breast cancer. The specific aromatase inhibitors being studied are exemestane, letrozole, and anastrozole.

The purpose of the study is to find out which method of treatment is more effective in preventing the cancer from coming back. Participants will receive either the concurrent or sequential treatment over a period of time, and their health will be monitored to see how well the treatment works. The study will also look at the safety of the treatments and any side effects that may occur. Some participants may receive a placebo as part of the study.

The trial will follow participants for several years to gather information on the long-term effects of the treatments. This includes tracking the time until any recurrence of the disease, the development of any new cancers, and overall survival. The study aims to provide valuable insights into the best way to combine chemotherapy and hormone therapy for women with hormone-responsive breast cancer.