Clinicopathological features and outcome for neuroendocrine neoplasms of gastroesophageal junction: A population‐based study

Background Gastroesophageal Junction neuroendocrine neoplasms (GEJ‐NENs) are rare and heterogeneous tumors. We aim to analyze the clinicopathlogical features and prognostic factors of GEJ‐NENs and to compare the outcome of GEJ‐NENs with other gastric NENs. Methods A total of 297 GEJ‐NENs patients were enrolled from 10 Chinese hospitals and 3152 gastric NENs patients, including 274 GEJ‐NENs, were retrieved from Surveillance, Epidemiology, and End Results (SEER) database. Results The clinical characteristics of GEJ‐NENs among different races were different. All Chinese patients had GEJ‐NENs of grade 3, with 67.7% of poorly differentiated NEC and 32.3% of MANEC. In SEER database, 70.8% of white, 62.5% of black, and 87.5% of AP patients had poorly differentiated/undifferentiated tumors. In Cox multivariate analysis, NEC/MANEC (HR 2.09, 95%CI 1.24‐3.56; P = 0.006), lymph node metastasis (HR 3.52, 95%CI 1.68‐7.34; P = 0.001), and distant metastases (HR 3.90, 95%CI 2.50‐6.08; P