Bone Metastasis in Esophageal Adenocarcinoma and Squamous Cell Carcinoma: A SEER-Based Study

Abstract

Background: Esophageal cancer (EC) is a common worldwide disease with a higher mortality rate. Studies on EC patients with bone metastasis (BM) are rare. Our study focused on the clinicopathological features of EC patients with BM using the Surveillance, Epidemiology and End Results (SEER) database to further explore the risk factors and survival for BM.Methods: According to the inclusion and exclusion criteria, EC patients with BM were extracted from the SEER database from 2010 to 2016. Univariable analysis and multivariable logistic regression were used to study the risk factors for BM. Univariable analysis and multivariable Cox regression were performed to reveal the survival and prognostic factors for BM. The competitive risk model was made to compare the association with BM among causes of death. Propensity score matching (PSM) was used to reduce the bias.Results: A total of 5314 patients were included in this study. Patients with BM had a worse prognosis before and after PSM. Male, middle esophagus, with brain metastasis, without lung metastasis, without liver metastasis were major independent risk factors of BM. Poorly differentiated and undifferentiated, with liver metastasis, with lung metastasis and without chemotherapy were major independent prognostic factors of BM.Conclusions: Compared to patients with other metastatic sites such as liver, brain and lung, patients with BM had a worse prognosis. Our findings provide recommendations about clinical guidelines including examination and treatment for EC patients with BM.