The role of endocrine therapies in reducing risk of recurrence in postmenopausal women with hormone receptor-positive breast cancer

SummaryHormone receptor-positive breast cancer is increasingly considered a chronic disease, as there remains an ongoing risk of local and distant relapse for years after diagnosis. While early recurrence risk peaks 2–3 years post diagnosis, the majority of breast cancer recurrences and deaths occur following 5 years of adjuvant tamoxifen. Aromatase inhibitors have achieved greater relative reductions in recurrence risk than tamoxifen alone and are now widely recommended as adjuvant therapy for postmenopausal women with hormone-sensitive breast cancer. Although both anastrozole and letrozole have demonstrated superior disease-free survival compared with tamoxifen, letrozole to date offers the greatest significant reduction in the risk of distant metastases in patients with hormone-sensitive breast cancer. Anastrozole and exemestane also reduce local and distant recurrence risk in the “switch setting” following 2–3 years of tamoxifen. Extended adjuvant letrozole, given after 5 years of tamoxifen, significantly reduces local and distant recurrence as well as mortality in patients with node-positive disease. Specialist nurses and nurse practitioners facilitate informed choice for breast cancer patients through explaining treatment options and side effects; they thus need an understanding of which treatment strategies reduce recurrence risk, especially the risk of distant metastases.