The Prevalence, Risk Factors for Bone Metastases Development and Prognosis in Gastric Cancer Patients: A Population-based Study.

OBJECTIVE: The objective of the present study was to explore the prevalence, risk and prognostic factors for bone metastases (BM) developement in patients with initial gastric cancer (GC). METHODS: A total of 30,817 patients with GC in the Surveillance, Epidemiology and End Results (SEER) database, diagnosed from 2010 to 2016, were used to investigate the incidence and associated risk factors for BM developments using multivariate logistic regression. Among those, 1397 and 1121 BM patients were selected to identify independent prognostic factors for BM overall survival (OS) and cancer-specific survival (CSS) using multivariate Cox regression respectively. RESULT: A total of 1397 (4.53%) GC patients were diagnosed with BM at initial diagnosis. Younger age (<60 years), white race, cardia cancer, signet ring cell, higher grade, tumor size between 2.1 and 4.0 cm, the presence of regional lymph nodes (RLN) metastases, brain metastases, liver metastases, and lung metastases were positively associated with BM development. Conversely, a lower T stage was negatively associated with BM development compared to the T4 stage. The median survival time for GC patients with BM decreased dramatically to 5 months. The presence of RLN metastases was an independent predictor of worse overall survival and cancer-specific survival. Conversely, T2 stage and chemotherapy were associated with better overall survival and cancer-specific survival. Additionally, patients with cardia cancer had favorable cancer-specific survival. CONCLUSION: The prognosis of gastric cancer patients with BM was dismal. Our findings of several risk factors for BM development and prognostic factors for BM patients could be useful for clinical surveillance and individualized treatment.