age, De novo metastatic breast cancer, metastasis pattern, prognosis, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282

Abstract 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