Comparing Anastrozole-Placebo to the Combination Anastrozole-ZD1839 in Postmenopausal Patients With Estrogen Receptor and/or Progesterone Receptor Metastatic Breast Cancer

Inclusion Criteria:

Female postmenopausal patients aged 18 years or older with newly diagnosed metastatic breast cancer.
Patients with recurrent disease during or after adjuvant tamoxifen or patients who are hormone therapy naïve are eligible for this trial.
A paraffin embedded tumor tissue block or slides from either the metastatic or primary tumor site is required.

Exclusion Criteria:

Patients cannot be on hormone replacement therapy while on study.
Prior chemotherapy received for metastatic disease is not allowed.
Previous treatment with tyrosine kinase inhibitors or aromatase inhibitors is not allowed.
Patients who have evidence of an active interstitial lung disease are not eligible.