Endoscopic ultrasonography in large gastric folds

Usefulness of endoscopic ultrasonography in preoperative TNM staging of gastric cancer

AIM: To evaluate the value of endoscopic ultrasono-graphy (EUS) in the preoperative TNM staging of gastric cancer.

METHODS: Forty-one patients with gastric cancer (12 early stage and 29 advanced stage) proved by esophagogastroduodenoscopy and biopsies preoperatively evaluated with EUS according to TNM (1997) classification of International Union Contrele Cancer (UICC). Pentax EG-3630U/Hitachi EUB-525 echo endoscope with real-time ultrasound imaging linear scanning 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-layer structure of the gastric wall. All patients underwent surgery. Diagnostic accuracy of EUS for TNM staging of gastric cancer was determined by comparing preoperative EUS with subsequent postoperative histopathologic findings.

RESULTS: The overall diagnostic accuracy of EUS in preoperative determination of cancer depth of invasion was 68.3% (41/28) and 83.3% (12/10), 60% (20/12), 100% (5/5), 25% (4/1) for T1, T2, T3, and T4, respectively. The rates for overstaging and understaging were 24.4% (41/10), and 7.3% (41/3), respectively. EUS tended to overstage T criteria, and main reasons for overstaging were thickening of the gastric wall due to perifocal inflammatory change, and absence of serosal layer in certain areas of the stomach. The diagnostic accuracy of metastatic lymph node involvement or N staging of EUS was 100% (17/17) for N0 and 41.7% (24/10) for N+, respectively, and 66% (41/27) overall. Misdiagnosing of the metastatic lymph nodes was related to the difficulty of distinguishing inflammatory lymph nodes from malignant lymph nodes, which imitate similar echo features. Predominant location and distribution of tumors 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.

CONCLUSION: EUS is a useful diagnostic method for preoperative staging of gastric cancer for T and N criteria. However, EUS evaluation of malignant lymph nodes is still unsatisfactory.

Endosonography in gastric lymphoma and large gastric folds

To establish a correct preoperative differential diagnosis between gastric lymphoma and cancer is essential but can be difficult as endoscopic biopsies can sometimes provide a low diagnostic yield. By EUS, infiltrative carcinoma tends to show a vertical growth in the gastric wall, while lymphoma tends to show mainly a horizontal extension. EUS provides an accurate staging of gastric lymphoma, showing the exact level of infiltration and the presence of perigastric lymph nodes, thus the physician can obtain an accurate prognosis for each patient and select the best form of treatment accordingly. The response to chemoradiotherapy can also be investigated very accurately by EUS. Large gastric folds are seen in a great number of benign and malignant conditions. Diagnosis represents a clinical challenge because etiology may be extremely varied and standard biopsies are often inconclusive. Different diseases show different levels of infiltration of the gastric wall, thus a characteristic echo-pattern helps for the differential diagnosis. Endosonography, used always in combination with biopsy, allows to rule out malignancies and to select the most appropriate treatment for each patient (medical or surgical).