Abstract:Objective: To investigate the diagnostic value of endoscopic ultrasonography and transabdominal ultrasonography in preoperative staging of gastric cancer. Method: EUS and US were carried out in 134 patients of gastric cancer diagnosed by gastroscope and pathology. The invasion depth, range and boundary of the lesions were observed. Local lymph node metastasis and the neighboring or remote organs metastasis were recorded. The results of EUS and US were compared with the results of operation and pathology. Results: The accuracy of US was similar to EUS in T staging(75.37% vs 76.12%), but the accuracy of EUS in T4 staging was obviously lower than US(29.17% vs 79.17%). The accuracy of US and EUS in N staging was 50.75% and 69.40%, with a statistical difference between them(P<0.05). US was slightly lower than EUS in N0 and N1 staging(76.92% vs 84.61%; 69.64% vs 71.43%), but there was no statistical difference(P>0.05). The accuracy of US was obviously higher than EUS in N2 and N3 staging(68.29% vs 34.15%; 66.67% vs 12.50%), and there was a statistical difference(P<0.05). US was obviously superior to EUS in M1 stage. The accuracy of M1 staging by US and EUS was 83.33% and 16.67% respectively(P<0.05). The accuracy of EUS and US in TNM staging was 64.18% and 66.42% respectively, but the accuracy of EUS combined with US increased to 79.10%. Conclusion: EUS and US can both be used in T1, T2 and T3 staging, and the accuracy of US is obviously higher than EUS in T4 staging. The accuracy of EUS is slightly higher than US in N0 and N1 staging, but there is also no statistic difference. US is obviously superior to EUS in N2, N3 and M1. Therefore, EUS combining with US can obviously increase the accuracy of TNM staging for gastric cancer patients.