Clinically used breast cancer markers such as estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 are unstable throughout tumor progression.

PURPOSE To investigate whether hormonal receptors and human epidermal growth factor receptor 2 (HER2) change throughout tumor progression, because this may alter patient management. PATIENTS AND METHODS The study cohort included female patients with breast cancer in the Stockholm health care region who relapsed from January 1, 1997, to December 31, 2007. Either biochemical or immunohistochemical (IHC)/immunocytochemical (ICC) methods were used to determine estrogen receptor (ER), progesterone receptor (PR), and HER2 status, which was then confirmed by fluorescent in situ hybridization for IHC/ICC 2+ and 3+ status.

FACT: an open-label randomized phase III study of fulvestrant and anastrozole in combination compared with anastrozole alone as first-line therapy for patients with receptor-positive postmenopausal breast cancer.

Purpose: To compare the effect of therapy with anastrozole versus a combination of fulvestrant and anastrozole in women in first relapse of endocrine-responsive breast cancer.

Patients And Methods: Postmenopausal women, or premenopausal women receiving a gonadotropin-releasing hormone agonist, with estrogen receptor- and/or progesterone receptor-positive disease at first relapse after primary treatment of localized disease were open-label randomly assigned to a fulvestrant loading dose (LD) regimen followed by monthly injection plus 1 mg of anastrozole daily or to 1 mg of anastrozole daily alone. The primary end point was time to progression (TTP).