The use of endocrine therapy.
Endocrine therapy is still a mainstay in the treatment of metastatic breast cancer. It has been observed that about one third of women with metastatic breast cancer will respond to endocrine therapy. This response rate is surprisingly consistent for a wide variety of endocrine approaches, with a few exceptions, such as the use of corticosteroids, androgens, or danazol for which the response rate appears lower. Endocrine therapy is, in general, considerably less toxic than single or combination chemotherapy, but toxicities within the endocrine therapies may vary considerably. Thus, the choice and optimal sequencing of endocrine maneuvers relate largely to minimizing toxicity and optimizing total duration of benefit. A number of newer endocrine approaches including the antiestrogens and aminoglutethimide have recently provided a variety of less toxic choices. Even more recently, compounds such as the LHRH agonists and antiandrogens are being tested, although their use remains experimental. Combinations of two or more endocrine therapies or of chemotherapy and endocrine therapy are currently, also a subject of considerable interest. No studies to date, however, have shown a clear advantage to concurrent chemotherapy endocrine combinations or to the use of two or more concurrent hormonal maneuvers, with the possible exception of the combination of prednisolone with tamoxifen or with oophorectomy, which has improved overall survival in two trials.