Treatment Patterns and Outcomes in Elderly Patients with Metastatic Breast Cancer: A Multicenter Retrospective Study

Purpose: Currently, there is little information regarding optimal treatment for metastatic breast cancer (MBC) in elderly patients. In this retrospective study, we examined a cohort of elderly patients with MBC receiving a range of treatments, in terms of demographic and clinicopathologic characteristics, treatment patterns, and outcomes. Methods: Patients aged 65 years and older, and diagnosed with MBC between 2003 and 2015, were identified from the databases of three academic hospitals in South Korea. A total of 161 cases were eligible for inclusion. We assessed clinicopathologic features, treatment patterns, and outcomes, using the available electronic medical records. Based on age at MBC diagnosis, patients were divided into three groups: 65 to 69, 70 to 74, and >= 75 years. Results: Most patients had received active treatment according to biologic subtype as in younger patients, although frequent dose modifications were observed during chemotherapy. The median overall survival (OS) for all patients was 30.3 months; age (>= 70 years), Eastern Co-operative Oncology Group (ECOG) performance status (PS) (>= 2), triple-negative cancer, and number of metastatic sites (>= 2) were significant poor prognostic factors for OS in multivariate analyses. All types of systemic treatments according to biologic subtype conferred more prolonged OS in patients receiving treatment. Patients aged >= 75 years were more likely to have a poor ECOG PS and advanced comorbidity, and tended to receive less intensive treatments compared to the other age groups. Conclusion: Elderly patients with MBC should not be excluded from receiving standard treatments prescribed for younger patients. Future research plans for elderly patients, especially aged >= 75 years with breast cancer, should include a geriatric assessment for identifying individuals at risk for treatment-related toxicity. Overall, this analysis will provide a better understanding of this population and help guide clinical care in real-world practice.