Adjuvant Systemic Therapy for Older Adults with Early-Stage Breast Cancer

There is a relative paucity of evidence to guide the adjuvant therapy of breast cancer in older adults. Herein, we review data from relevant clinical trials and retrospective analyses that assess systemic therapies in older adults. Chemotherapy, endocrine therapy, HER2-directed agents and bisphosponates in the adjuvant setting are discussed. Meta-analyses, such as the Oxford overview, suggest a decreasing benefit of chemotherapy with age. However, prospective trials do support a benefit from the addition of chemotherapy to endocrine therapy in older adults. In contrast to chemotherapy, the value of endocrine therapy appears to increase with age. In addition, available subset analyses suggest that the benefit from aromatase inhibitors relative to tamoxifen is independent of age. The use of HER2-directed therapy in older adults is challenged by the relatively low enrolment of this subset in prospective clinical trials. Nonetheless, the extent of enrolment may be proportional to the frequency of HER2 overexpression in this population. Finally, there are little data to support the use of adjuvant bisphosphonate therapy in older adults – ongoing prospective trials may address this issue. Each of the aforementioned therapeutic strategies will be augmented by efforts to personalize therapy for older adults. Clinical tools such as the geriatric assessment and biologic assays, such as the 21-gene recurrence score, may ultimately play a role in treatment algorithms for this unique demographic.