title: Sequencing of endocrine therapy in postmenopausal women with advanced breast cancer.
abstract: The introduction of the nonsteroidal aromatase inhibitor (NS-AI) anastrozole as an alternative to tamoxifen for adjuvant therapy of women with resected hormone receptor-positive breast cancer has added a management category into which patients presenting with metastatic disease can be placed. There are now essentially three such categories: (a) tamoxifen sensitive (no prior AI); (b) tamoxifen resistant (no prior AI); and (c) NS-AI resistant (no prior tamoxifen). Well-conducted Phase III trials provide evidence for choosing first-line therapy for advanced disease in categories a and b. In tamoxifen-sensitive patients, one can choose either NS-AI, anastrozole, or letrozole. In tamoxifen-resistant patients, one can choose either of the NS-AIs, the steroidal AI exemestane, or the estrogen receptor down-regulator fulvestrant. The situation is quite different for patients in category c. There are no Phase III trials of agents in patients who have experienced disease progression on a NS-AI. Phase II data are available for exemestane and high-dose estrogens, and retrospective data are available for tamoxifen and fulvestrant. Additional clinical trials are needed to determine an optimal sequencing strategy.
authors.affiliation: Division of Medical Oncology, Mayo Clinic, Rochester, Minnesota, USA. ingle.james@mayo.edu
authors.forename: James N
authors.initials: JN
authors.lastname: Ingle
mesh_terms: D000730:Androstadienes / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000494:pharmacology; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant; D002986:Clinical Trials as Topic; D018450:Disease Progression; D005260:Female; D006801:Humans; D009362:Neoplasm Metastasis; D009376:Neoplasms, Hormone-Dependent / Q000378:metabolism; D017698:Postmenopause; D011960:Receptors, Estrogen / Q000378:metabolism; D013629:Tamoxifen / Q000627:therapeutic use
chemical_list: D000730:Androstadienes; D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D013629:Tamoxifen; C056516:exemestane