The metastasis patterns and their prognostic features in patients with de novo metastatic breast cancer of different ages

PURPOSE: The prognostic outcomes of metastasis patterns in patients with de novo metastatic breast cancer (dnMBC) of different ages are unknown. Our study used a large‐scale data to investigate the metastasis patterns and prognostic features in dnMBC of different ages. METHODS: Total 24,698 women with dnMBC in the Surveillance, Epidemiology and End Results database (2010–2018) were divided into three groups by age. Chi‐squared test was used to compare metastasis patterns and logistic regression was performed to investigate the risk of age and specific organ metastases. Kaplan–Meier survival curves were used to compare the overall survival. RESULTS: In three groups, young group had the largest proportion of liver metastases (35.2% vs. 28.2% vs. 21.1%, p < 0.001), and elderly group had the largest proportion of lung metastases (22.6% vs. 30.0% vs. 35.0%, p < 0.001) and the lowest proportion of bone metastases (65.7% vs. 67.6% vs. 64.4%, p < 0.001). In young group, patients with liver metastases had better prognosis than patients with lung metastases (MST: 34 months vs. 29 months, p = 0.041), but in middle‐aged and elderly groups, the prognosis of lung metastases was better than that of liver metastases (MST in middle‐aged group: 24 months vs. 20 months, p = 0.002; MST in elderly group: 12 months vs. 6 months, p < 0.001). CONCLUSION: DnMBC patients at different age have distinct metastasis patterns and prognostic features. The findings lend support to consideration of tailored management and surveillance strategies for different age patients.