The introduction of adjuvant systemic therapy led to a significant improvement in post-surgical survival and a reduction in disease relapse. Approximately 75–80% of all breast cancers are hormone-dependent based on the presence of ER and/or PR on tumor cells. Patients with HR+ breast cancer less than 5 mm and treated with only endocrine therapy have usually very good prognosis. They typically are not treated with adjuvant chemotherapy. The patients with stage III HR+ breast cancer still require adjuvant chemotherapy since they carry high risk of recurrence without chemotherapy. Many patients with HR+ HER2 negative breast cancer fall in between these two categories, and they are called as intermediate risk group based on clinicopathological variables, genomic tests or online risk calculators. The minimum duration of adjuvant endocrine treatment is 5 years; however, patients with high risk factors including positive lymph node should be treated with the endocrine therapy up to 10 years either with tamoxifen alone or sequentially with aromatase inhibitors (AI) in postmenopausal women. Adjuvant bisphosphonates reduce bone recurrence and improve survival in postmenopausal women with early stage breast cancer.
Part of the book: Breast Cancer and Surgery