Prognostic Significance of Metastatic Lymph Node Number, Ratio and Station in Gastric Neuroendocrine Carcinoma

The objective of this study was to analyze the prognostic significance of metastatic lymph node status in gastric neuroendocrine carcinoma (GNEC) patients following radical gastrectomy. A consecutive series of 73 patients who underwent gastrectomy between 1999 and 2011 for GNEC was retrospectively reviewed. Indexes of lymph node involvement (the pN classification, metastatic lymph node number [MLNn], ratio [MLNr], and station [MLNs]) and other clinicopathological data were analyzed. Fifty-four patients met the inclusion criteria and were enrolled in the study. Among them, 44 patients (81 %) were found to have lymph node metastases. The median survival time of the entire cohort was 63.2 (range, 14–153) months with 3- and 5-year survival rates of 88.9 and 47.9 %, respectively. The median total number of lymph nodes, MLNn, and MLNr were 19 (range, 10–56), 5 (range, 1–21), and 25 % (6–100 %), respectively. Cox regression analysis revealed pN classification = 1, MLNn >2, MLNr >0.1, and MLNs = 2, and distant metastases influenced prognosis independently (P = 0.0266, 0.0091, 0.0031, 0.0119, and 0.0021, respectively). In addition to the pN classification, indexes of metastatic lymph node involvement, including MLNn, MLNr, and MLNs, were all significant predictors of survival in GNEC patients. Distant metastasis was also a significant prognostic factor. These indexes proved to be accurate and important supplements to survival factors, which may improve risk classification of GNEC patients.