Predicting the survival benefit of local surgery in patients aged 70 years or older with stage IV breast cancer: A population-based analysis.

PURPOSE: The aim of this study was to establish individualized nomograms to predict survival outcomes in older female patients with stage IV breast cancer who did or did not undergo local surgery, and to determine which patients could benefit from surgery. METHODS: A total of 3,129 female patients with stage IV breast cancer aged ≥70 years between 2010 and 2015 were included in the Surveillance, Epidemiology, and End Results program. Multivariate Cox regression analysis was used to identify risk factors for overall survival (OS) and breast cancer-specific survival (BCSS). Survival analysis was performed using the Kaplan-Meier plot and log-rank test. Nomograms and risk stratification models were constructed. RESULTS: Patients who underwent surgery had better OS (HR = 0.751, 95% CI [0.668-0.843], P < 0.001) and BCSS (HR = 0.713, 95% CI [0.627-0.810], P < 0.001) than patients who did not undergo surgery. Patients with human epidermal growth factor receptor 2-positive, lung or liver metastases may not benefit from surgery. In the stratification model, low-risk patients benefited from surgery (OS, HR = 0.688, 95% CI [0.568-0.833], P < 0.001; BCSS, HR = 0.632, 95% CI [0.509-0.784], P < 0.001), while patients in the high-risk group had similar outcomes (OS, HR = 0.920, 95% CI [0.709-1.193], P = 0.509; BCSS, HR = 0.953, 95% CI [0.713-1.275], P = 0.737). CONCLUSION: Older female patients with stage IV breast cancer who underwent surgery had better OS and BCSS than those who did not in each specific subgroup. Patients in low- or intermediate-risk group benefit from surgery while those in the high-risk group do not.