Combined Endocrine Therapy for Breast Cancer— New Life for an Old Idea?

Extract

Endocrine therapy has been a mainstay of breast cancer treatment for more than 100 years. The first interventions, oophorectomy for premenopausal women and pharmacologic doses of estrogen for postmenopausal women, have been supplanted by targeted therapy, including selective estrogen receptor modulators (SERMs) like tamoxifen, luteinizing hormone-releasing hormone (LHRH) agonists, and aromatase inhibitors. The initial attempts to combine hormonal therapies generally led to the finding of increased response rates but at the expense of higher toxicity and without an obvious survival advantage when compared with the survival with sequential monotherapy. These results have led to the current practice of serial hormonal manipulation in advanced breast cancer—i.e., the use of one endocrine therapy until disease progression, followed by a second intervention until its failure and so on. In practice, this means that a strategy of tamoxifen followed by ovarian ablation or the reverse has been the norm for premenopausal women with metastatic breast cancer who are believed to be candidates for endocrine therapy (1).