[Surgical treatment of gastric carcinoma]

External Validation of an Eastern Asian Nomogram for Survival Prediction After Gastric Cancer Surgery in a European Patient Cohort

Several nomograms for survival prediction after curative gastric cancer surgery have been published over the recent years. Previous validation studies failed to prove applicability of Eastern Asian nomograms in Western patients. Here we present data on a validation analysis of a newly developed Korean nomogram in a German patient cohort.Among a total of 2771 patients having been treated in the Department of Surgery of the Technische Universitaet Muenchen from 1982 to 2008, 908 patients were eligible to undergo this analysis. Patients were treated according to Japanese Gastric Cancer guidelines and followed up on a regular basis for at least 60 months postoperatively. Baseline characteristics were compared using χ-testing. Survival analyses were computed with the Kaplan-Meier method and multivariate regression analysis models. The C-statistics and Hosmer-Lemeshow chi-square statistics were computed for comparisons of the nomogram's predictive ability.All baseline characteristics were significantly different (P < 0.0001) between Korean and German patients except Union Internationale Contre le Cancer-stages (P = 0.427). Multivariate regression analysis revealed the same predictive factors for overall survival in the German and Korean cohorts, respectively, with the exception of tumor size >10 cm and an exclusive correlation of whole stomach spread and pN1-stage for German patients only. The C-index was 0.76, representing an adequate value for predictability of the Korea nomogram in German patients. The Hosmer-Lemeshow statistic implied applicability of the nomogram in the TUM-cohort.A newly developed multicenter Korean nomogram for survival prediction after curative gastric cancer surgery may be applicable for estimating survival prognosis in Western (European) patients.

Alterations of tumor-related genes do not exactly match the histopathological grade in gastric adenocarcinomas

AIM: To investigate the diverse characteristics of different pathological gradings of gastric adenocarcinoma (GA) using tumor-related genes.

METHODS: GA tissues in different pathological gradings and normal tissues were subjected to tissue arrays. Expressions of 15 major tumor-related genes were detected by RNA in situ hybridization along with 3’ terminal digoxin-labeled anti-sense single stranded oligonucleotide and locked nucleic acid modifying probe within the tissue array. The data obtained were processed by support vector machines by four different feature selection methods to discover the respective critical gene/gene subsets contributing to the GA activities of different pathological gradings.

RESULTS: In comparison of poorly differentiated GA with normal tissues, tumor-related gene TP53 plays a key role, although other six tumor-related genes could also achieve the Area Under Curve (AUC) of the receiver operating characteristic independently by more than 80%. Comparing the well differentiated GA with normal tissues, we found that 11 tumor-related genes could independently obtain the AUC by more than 80%, but only the gene subsets, TP53, RB and PTEN, play a key role. Only the gene subsets, Bcl10, UVRAG, APC, Beclin1, NM23, PTEN and RB could distinguish between the poorly differentiated and well differentiated GA. None of a single gene could obtain a valid distinction.

CONCLUSION: Different from the traditional point of view, the well differentiated cancer tissues have more alterations of important tumor-related genes than the poorly differentiated cancer tissues.