Anastrozole and ZD 1839 in Treating Postmenopausal Women With Metastatic Breast Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed breast cancer * Metastatic or locally advanced unresectable disease * At least 1 measurable target lesion that has not been irradiated * New lesions in a previously irradiated field allowed as sites of measurable disease * Progressive disease after more than 2 months of aromatase inhibitor therapy * No known CNS disease or unevaluated CNS symptoms suggestive of brain metastases * Hormone receptor status: * Estrogen receptor or progesterone receptor positive PATIENT CHARACTERISTICS: Age * 18 and over Sex * Female Menopausal status * Post-menopausal by 1 of the following criteria: * Age 50 and over and has not menstruated during the past year or has castrate follicle-stimulating hormone (FSH) levels (greater than 40 IU/L) * Under age 50 and has castrate FSH levels * Received prior bilateral oophorectomy and has castrate FSH levels Performance status * ECOG 0-2 Life expectancy * At least 12 weeks Hematopoietic * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * ALT or AST no greater than 2.5 times ULN (5 times ULN if liver metastases present) Renal * Creatinine no greater than 1.5 times ULN Cardiovascular * No history of congestive heart failure requiring therapy * No ventricular arrhythmia requiring therapy * No unstable angina pectoris * No myocardial infarction within the past 6 months Other * Able to swallow oral medication * No other malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix * No known malabsorption condition or other condition that would impair absorption of study drug * No active infection * No other concurrent medical condition that would preclude study * No known severe hypersensitivity to ZD 1839 or any excipients PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * No prior chemotherapy except in adjuvant setting * No concurrent chemotherapy for breast cancer Endocrine therapy * See Disease Characteristics * More than 30 days since other prior hormonal therapy (including hormone replacement therapy and megestrol) * Concurrent steroids for other reasons besides skin toxicity allowed * No other concurrent hormonal therapy (including megestrol) for breast cancer Radiotherapy * See Disease Characteristics Surgery * Recovered from prior oncologic or other major surgery * No concurrent ophthalmic surgery Other * More than 30 days since prior anticancer therapy * More than 30 days since prior non-approved or investigational drugs * No prior epidermal growth factor receptor or HER2 blockers * No concurrent phenytoin, carbamazepine, barbiturates, rifampicin, phenobarbital, Hypericum perforatum, or systemic retinoids * No other concurrent investigational therapy for breast cancer * Concurrent bisphosphonates for metastatic bone disease allowed