Brain metastasis originated from gastric cancer: its clinicopathological characteristics and survival outcome

Objective: The frequency and prognostic factors of brain metastasis(BM) originated from gastric cancer(GC) remain unclear. The purpose of this study was to clarify the current knowledge of BM and determine its risk factors and survival outcome. Methods A total of 9,278 stage IV GC patients were retrospectively identified from the Surveillance, Epidemiology, and End Results(SEER) database. Clinicopathological features and survival outcomes between patients with and without BM were compared, and significant prognostic factors were determined. Results The frequency of BM in stage IV patients was 2.2%(203/9,278), and 52.7%(107/203) of BM patients presented synchronous extracranial metastases at the time of diagnosis. Younger age(< 65 years old) and proximal GC were significantly associated with BM. The patients with BM had a shorter median cancer-specific survival(CSS)(3.0 months [95% CI: 2.21–3.79] vs 7.0 months [95% CI:6.73–7.27], P < 0.001) and overall survival(OS)(3.0 months [95%CI:2.27–3.73] vs 6.0 months [95%CI:5.77–6.23], P < 0.001) than those without BM. For patients with BM, the presence of synchronous extracranial metastases was significantly associated with shorter median CSS(3.0 months [95%CI: 2.30–3.70] vs 4.0 months [95%CI: 2.69–5.31], P = 0.031). However, there was no correlation between the number of extracranial metastatic organs and survival outcomes. Poorly differentiated/undifferentiated adenocarcinoma(HR:1.876, 95%CI:1.231–2.858, P = 0.003) and the presence of extracranial metastasis(HR:1.420, 95%CI:1.003–2.010, P = 0.048) were independent predictive factors for poor survival of patients with BM. Conclusions Brain metastasis originated from GC was not common, but survival outcome was extremely poor. For early detection of brain metastasis, it is necessary to pay more attention to patients with risk factors.