Accuracy of endoscopic ultrasound in preoperative T and N staging of gastric cancer: results of single-center retrospective analysis

The optimal treatment strategy for patients with early and locally advanced forms of gastric cancer directly depends on the stage of TNM, which determines the importance of accurate preoperative staging. In accordance with international guidelines, the combination of gastroscopy and endoscopic ultrasound (EUS) is an integral part of the standard examination protocol.

Aim. Assess the accuracy of EUS in assessing the T and N stage in gastric cancer.

Materials and methods. Patients with gastric cancer who received surgical treatment without prior chemotherapy were included in the study. All patients were staged by gastroscopy with EUS and CT scan. Following radical gastric resection, the pathological T-stage (pT) and N-stage (pN) were compared with preoperative stage (uT-stage and uN-stage).

Results. 174 patients were included in the study. The sensitivity of EUS ranged from 24 (for T4) to 63.9% (for T2). Specificity ranged from 65.9 (for T2) to 92.4% (for T4). Accuracy was 70.52, 65.32, 72.99 and 81.03% for T1, T2, T3 and T4 respectively. The T-stage was determined correctly in 66.7% of cases with T1a, in 50% of cases with T1b, in 32.9% of cases with T2, in 44.7% of cases with T3, and in 33.3% of cases with T4a. In patients with T2 tumors, where the greatest frequency of misstaging was observed, underestimation of the T-stage occurred in 30% of cases, overestimation – in 37.1% of cases. For N-staging, EUS has a sensitivity of 23.5%, specificity of 89.6% and an accuracy of 63.79%.

Conclusion. EUS is mandatory part of the initial staging of patients with gastric cancer. For any T-stage, EUS often overestimated the stage rather than underestimated the true extent of tumor invasion. The accuracy of diagnosis is influenced by histological features of the tumor, such as the diffuse type and signet-ring cell carcinoma. Diagnostic value of EUS in N-staging is low.