Suppression of Ovarian Function With Either Tamoxifen or Exemestane Compared With Tamoxifen Alone in Treating Premenopausal Women With Hormone-Responsive Breast Cancer

Inclusion Criteria

• Premenopausal women (estradiol [E2] in the premenopausal range [according to institution parameters]) who meet the following criteria:
• Patients who did not receive chemotherapy should be randomized within 12 weeks after definitive surgery; such patients should have estradiol (E2) in the premenopausal range following surgery; the only patients who do not require testing of estradiol (E2) to confirm premenopausal status are those who have been menstruating regularly during the 6 months prior to randomization and have not used any form of hormonal contraception or any other hormonal treatments during the 6 months prior to randomization
• Patients who received prior adjuvant and/or neoadjuvant chemotherapy should be randomized after completing chemotherapy and within 8 months of the final dose of chemotherapy as soon as premenopausal status is confirmed; all such patients should have premenopausal status confirmed by an estradiol (E2) in the premenopausal range between 2 weeks and 8 months after completing chemotherapy
• Adjuvant trastuzumab (Herceptin ®) is allowable, and is not considered to be chemotherapy for eligibility timing determination
• Patients with temporary chemotherapy-induced amenorrhea who regain premenopausal status within eight months of the final dose of chemotherapy are eligible; (please note that some patients taking tamoxifen or aromatase inhibitors, even without evidence of menses, may have ovarian function recovery following chemotherapy and resume estradiol secretion); in patients wishing to participate in the study, with postmenopausal hormone levels shortly after chemotherapy, it is recommended to recheck their estradiol level at a later timepoint within 8 months of completing chemotherapy, even in the absence of return of menses
• Histologically proven, resected breast cancer; pathology material should be available for submission for central review as part of the quality control measures for this protocol
• Patients must have hormone receptor positive tumors; if there is more than one breast tumor, each tumor must be hormone receptor positive; hormone receptors must be determined using immunohistochemistry; estrogen receptor (ER) and/or progesterone receptor (PgR) must be greater than or equal to 10% of the tumor cells positive by immunohistochemical evaluation; biochemical determination alone is not acceptable
• The tumor must be confined to the breast and axillary nodes without detected metastases elsewhere, with the exception of tumor detected in internal mammary chain nodes by sentinel node procedure; patients who received neoadjuvant therapy must have had operable disease prior to neoadjuvant treatment to be eligible; patients who had a pathological evaluation with tru cut or core biopsy of invasive breast cancer prior to neoadjuvant therapy and were found to have no invasive tumor in the pathological specimen from definitive surgery are eligible; for these patients, pre-neoadjuvant tumor characteristics will be used for defining eligibility; in case of persistent disease, pathology findings from the definitive surgery should be used
• Patients must have had proper surgery for primary breast cancer with no known clinical residual loco-regional disease:
• A total mastectomy; radiotherapy is optional after mastectomy OR
• A breast-conserving procedure (lumpectomy, quadrantectomy or partial mastectomy with margins clear of invasive cancer and ductal breast carcinoma in situ [DCIS]); the local pathologist must document negative margins of resection in the pathology report; if all other margins are clear, a positive posterior (deep) margin is permitted, provided the surgeon documents that the excision was performed down to the pectoral fascia and all tumor has been removed; likewise, if all other margins are clear, a positive anterior (superficial; abutting skin) margin is permitted provided the surgeon documents that all tumor has been removed; radiation therapy to the conse