Randomized Study Comparing Tamoxifen vs. Tamoxifen + Aminoglutethimide in Postmenopausal Receptor-positive Patients

Inclusion Criteria: * Postmenopausal patients with histologically verified, locoradically treated, invasive or minimally invasive breast cancer * Hormone receptor-positive status * More than 6 histologically examined lymph nodes * Laboratory parameters 1. hematopoiesis: \> 3500/µl leucocytes, \> 100,000/µl thrombocytes 2. renal function: creatinin \< 1.5mg% 3. hepatic function: GOT \< 2.5 x UNL 4. bilirubin: \< 1.5mg % 5. metabolic parameters: Na, Ca, K in normal range, normal level of blood sugar * Concluded healing process following surgery * Less than 4 weeks interval since surgery * Informed consent Exclusion Criteria: * Premenopausal patients, non-determinable menopausal status * Previous radiotherapy, chemotherapy or endocrine treatment * Generalized disease (as verified by lung X-ray, skeletal X-ray, liver ultrasound) * Contraindications against tamoxifen or anastrozole * T4 tumors; carcinoma in situ * Lacking compliance or understanding of disease * Karnofsky Index \< 3 * Serious concomitant disease * Septic complications, systemic infections or infectious local processes * Bilateral ovariectomy or ovarian irradiation * Second carcinoma or status post second carcinoma (except for treated squamous cell carcinoma of the skin or cervical carcinoma in situ)