AIM:To evaluate the value of endoscopic ultrasono-graphy (EUS) in the preoperative TNM staging of gastriccancer.METHODS :Forty-one patients with gastric cancer(12 early stage and 29 advanced stage) provedby esophagogastroduodenoscopy and biopsiespreoperatively evaluated with EUS according to TNM(1997) classification of International Union ContreleCancer (UICC).Pentax EG-3630U/Hitachi EUB-525 echoendoscope with real-time ultrasound imaging linearscanning transducers (7.5 and 5.0 MHz) and Dopplerinformation was used in the current study.EUS stagingprocedures for tumor depth of invasion (T stage) wereperformed according to the widely accepted five-layerstructure of the gastric wall.All patients underwentsurgery.Diagnostic accuracy of EUS for TNM stagingof gastric cancer was determined by comparingpreoperative EUS with subsequent postoperativehistopathologic findings.RESULTS:The overall diagnostic accuracy of EUS inpreoperative determination of cancer depth of invasionwas 68.3% (41128) and 83.3% (12110),60% (20112),100% (5/5),25% (4/1) for T1,T2,T3,and T4,respectively.The rates for overstaging and understagingwere 24.4% (41/10),and 7.3% (41/3),respectively.EUStended to overstage T criteria,and main reasons foroverstaging were thickening of the gastric wall due toperifocal inflammatory change,and absence of serosallayer in certain areas of the stomach.The diagnosticaccuracy of metastatic lymph node involvement or Nstaging of EUS was 100% (17/17) for NO and 41.7%(24/10) for N+,respectively,and 66% (41/27) overall. Misdiagnosing of the metastatic lymph nodes was relatedto the difficulty of distinguishing inflammatory lymphnodes from malignant lymph nodes,which imitate similarecho features.Predominant location and distribution oftumors in the stomach were in the antrum (20 patients),and the lesser curvature (17 patients),respectively.Three cases were found as surgically unresectable (T4 N+),and included as being correctly diagnosed by EUS. AIM: To evaluate the value of endoscopic ultrasono-graphy (EUS) in the preoperative TNM staging of gastriccancer. METHODS: Forty-one patients with gastric cancer (12 early stage and 29 advanced stage) proved by esophagogastroduodenoscopy and biopsiespreoperatively evaluated as EUS according to TNM (1997) classification of International Union ContreleCancer (UICC). Pentax EG-3630U / Hitachi EUB-525 echoendoscope with real-time ultrasound imaging linearscanning transducers (7.5 and 5.0 MHz) and Doppler information was used in the current study. EUS staging procedures for tumor depth of invasion (T stage) were performed according to the widely accepted five-layers structure of the gastric wall. All patients underwentsurgery. Diagnostic accuracy of EUS for TNM staging of gastric cancer was determined by comparing preoperative EUS with subsequent postoperativehistopathologic findings .RESULTS: The overall diagnostic accuracy of EUS in preoperative determination of cancer depth of invasionwas 68.3% (41128) and The percentages for overstailing and decreasingwere 24.4% (41/83) were 83.3% (12110), 60% (20112), 100% (5/5), 25% 10), and 7.3% (41/3), respectively. EUStended to overstage T criteria, and main reasons for overstaking were thickening of the gastric wall due toperifocal inflammatory change, and absence of serosallayer in certain areas of the stomach. The diagnosticaccuracy of metastatic Misdiagnosing of the metastatic lymph nodes was related to the difficulty (41/27) for NO and 41.7% (24/10) for N +, respectively, and 66% (41/27) overall. of distinguishing inflammatory lymphnodes from malignant lymph nodes, which imitate similarecho features. Predominant location and distribution of tumors in the stomach were in the antrum (20 patients), and the lesser curvature (17 patients), respectively. Thh cases were found as surgically unresectable ( T4 N +), and included as being correctly diagnosed by EUS.