Prognostic Threshold of Neuroendocrine Differentiation in Gastric Carcinoma: a Clinicopathological Study of 945 Cases

PURPOSE: The significance of neuroendocrine differentiation (NED) in gastric carcinoma (GC) is controversial, leading to ambiguous concepts in traditional classifications. This study aimed to determine the prognostic threshold of meaningful NED in GC and clarify its unclear features in existing classifications. MATERIALS AND METHODS: Immunohistochemical staining for synaptophysin, chromogranin A, and neural cell adhesion molecule was performed for 945 GC specimens. Survival analysis was performed using the log-rank test and univariate/multivariate models with percentages of NED (PNED) and demographic and clinicopathological parameters. RESULTS: In total, 275 (29.1%) cases were immunoreactive to at least 1 neuroendocrine (NE) marker. GC-NED was more common in the upper third of the stomach. PNED, and Borrmann's classification and tumor, lymph node, metastasis stages were independent prognostic factors. The cutoff PNED was 10%, beyond which patients had significantly worse outcomes, although the risk did not increase with higher PNED. Tumors with ≥10% NED tended to manifest as Borrmann type III lesion with mixed/diffuse morphology and poorer histological differentiation; the NE components in this population mainly grew in insulae/nests, which differed from the predominant growth pattern (glandular/acinar) in GC with <10% NED. CONCLUSIONS: GC with ≥10% NED should be classified as a distinct subtype because of its worse prognosis, and more attention should be paid to the necessity of additional therapeutics for NE components.

Clinicopathologic Significance of Gastric Adenocarcinoma with Neuroendocrine Features

PURPOSE: Composite neuroendocrine-exocrine carcinomas are malignancies that have two distinct components residing within the same tumor: an adenocarcinomatous portion and a neuroendocrine portion. This is rare in gastric cancers; however, poorly differentiated adenocarcinomas can sometimes reveal evidence of neuroendocrine features (NEF) or be 'mixed endocrine and exocrine carcinomas'. This study aimed to review NEF in gastric adenocarcinoma and to evaluate its prognostic significance. MATERIALS AND METHODS: We selected 29 patients who were diagnosed with gastric adenocarcinoma with NEF and received gastrectomies at the Department of Surgery, Ajou University Hospital between January 2001 and December 2009. We analyzed the clinicopathologic features of gastric cancer with NEF and the prognosis associated with such tumors. RESULTS: The pathologic result with respect to TNM staging of the gastric cancers with NEF were as follows: 5 cases of T1, 5 cases of T2, 10 cases of T3, and 9 cases of T4. There were 7 cases of N0, 7 cases of N1, 8 cases of N2 and 7 cases of N3. The staging of patients with NEF was higher than that of patients without NEF. Especially tumor lymphovascular invasion rate was 82.8%. The overall survival of patients with gastric cancer characterized by NEF was 73.8 months. CONCLUSIONS: Positive NEF status might be correlated with clinicopathologic parameters such as a high stage and high frequency of regional lymph node metastasis.