Current controversies in extended adjuvant endocrine therapy for early breast cancer

Hormone receptor positive breast cancer is responsible for the majority of breast cancer deaths. The risk for disease recurrence that is lower in the first 5 years after primary treatment than for hormone receptor negative breast cancer remains relatively high even after 15 years. Late recurrences can be prevented or at least further delayed with extended endocrine therapy. Its optimal duration and treatment tailoring is discussed in the present review.

Recently, the results of Adjuvant Tamoxifen, Longer Against Shorter and adjuvant Tamoxifen--To offer more, two very large adjuvant trials exploring the benefit of extending tamoxifen treatment beyond 5 years, were reported, adding controversy to what was believed to be the optimal duration of adjuvant tamoxifen. Aromatase inhibitors have proven to have disease-free survival advantage when used after 5 years of tamoxifen with a delay of up to 2.8 years. Further data on sequencing endocrine agents are eagerly awaited.

In summary, at least further 4 years of aromatase inhibitor treatment after the first 5 years of adjuvant tamoxifen is recommended in postmenopausal endocrine responsive early breast cancer, nowadays. The value of extended tamoxifen therapy is still controversial, though it might be of interest especially in premenopausal patients. Tailoring treatment according to risk of disease recurrence, patient life expectancy, comorbidity, risk factors for cardiovascular disease or osteoporosis and compliance is necessary.