Breast cancer is the most frequently diagnosed malignancy in women. Aging is an independent predictor of adverse treatment outcomes, including an increase in multimorbidity, which is associated with higher mortality, functional impairment, poor quality of life (QoL) and elevated healthcare utilization and costs. Geriatric screening tools and assessments that evaluate a patient's fitness and frailty status are becoming increasingly important in providing a comprehensive patient profile and developing an optimized treatment plan. However, older patients are currently underrepresented in clinical trials, resulting in a lack of published data. This article examines the results from recent clinical trials in breast cancer, with a focus on older patient populations.