Duration of adjuvant endocrine therapy of breast cancer: how much is enough?

PURPOSE OF REVIEW: To describe the current status regarding the duration of adjuvant tamoxifen and/or aromatase inhibitors in women with early-stage hormone receptor positive breast cancer. RECENT FINDINGS: Women with early-stage breast cancers that express estrogen and/or progesterone receptors benefit from adjuvant hormonal therapy with antiestrogen drugs. Five years of tamoxifen is the standard to which other approaches have been compared. In premenopausal women, a total of 5 years of adjuvant hormonal therapy using tamoxifen is the preferred approach. In postmenopausal women, aromatase inhibitors alone or in sequence after tamoxifen for 5 years has become the standard of care. The use of antiestrogen therapy for longer than 5 years has been studied in several trials. There is a suggestion that there may be improved disease-free survival in some subgroups, but the clinical significance and magnitude of this benefit remains an open question. Some particularly high-risk subgroups may be candidates for extended adjuvant therapy. In addition to the efficacy of adjuvant hormonal therapy, careful attention must be paid to compliance with the prescribed medication, management of side effects, and evaluation of costs. SUMMARY: There are many approaches to the adjuvant hormonal therapy of breast cancer supported by large trials. No one approach is uniquely superior to others. Longer follow-up may lead to more specific recommendations. Adjuvant hormonal therapy for women with hormone receptor positive breast cancer plays a critical role in the management of early stage hormone receptor positive breast cancer.