Evaluation of endoscopic ultrasonography as an indicator for surgical treatment of gastric cancer

The emerging role of endoscopic ultrasonography in cancer staging

The management of solid organ cancers relies on accurate staging. Once distal metastasis has been excluded by conventional radiographic methods, local staging of the tumor and its nodal involvement is essential to determine the most optimal therapeutic approach. Many radiographic imaging modalities are unable to determine subtle tumor involvement. However, the emergence of endoscopic ultrasonography (EUS) has given promise to improved staging with its unique ability to examine tumors from within the gastrointestinal lumen with extremely close proximity. An additional advantage is the ability to perform fine-needle aspiration (FNA) biopsy to confirm or exclude tumor involvement. Many studies have shown superior accuracy in staging with EUS and EUS-FNA for tumors of the esophagus, stomach, pancreas, rectum, and mediastinum, including lung cancer. This review illustrates the principles of EUS and its role in staging of a variety of cancers and particularly its role alongside other imaging modalities.

Endoscopic ultrasonography in preoperative staging of gastric cancer: determination of tumor invasion depth, nodal involvement and surgical resectability

AIM: Current study was aimed to evaluate the usefulness of EUS in TNM staging of gastric cancer by comparing EUS preoperative staging with pathological findings, and the preliminary exploration of possible reasons for overstaging and understaging phenomenon was especially intended.

METHODS: A total of 35 patients with histologically confirmed gastric adenocarcinoma were referred to EUS and staged preoperatively by using the TNM system. The preoperative endosonographic results were compared with the histopathological staging.

RESULTS: The overall accuracy of EUS for determination of the T stage was 80.0%, and for T1, T2, T3, and T4 was 100%, 71.4%, 87.5% and 72.7%, respectively. For N stage, EUS had the accuracy of 68.6%, with sensitivity and specificity of 66.7% and 73.7%, respectively. Resectability was predicted with sensitivity and specificity of 87.5% and 100%, respectively.

CONCLUSION: EUS is an accurate staging modality in most cases, with a few exceptions of overstaging and understaging. Patients with gastric cancers can benefit from preoperative EUS staging for establishing individualized therapy. However, EUS criteria to differentiate benign from malignant nodes still need to be further defined by future studies.

Gastrointestinal endoscopic ultrasonography

Although conventional endoscopy provides excellent visualization of gastrointestinal mucosa, it provides little information about intramural or nearby extramural lesions. The imaging of intraabdominal structures by conventional transabdominal ultrasound is degraded by ultrasound energy attenuation with distance. The provision of an ultrasound probe on a flexible gastrointestinal endoscope, to form an echoendoscope, provides excellent imaging of the gastrointestinal wall and of adjacent extramural structures. During the last two decades, endoscopic ultrasound, using an echoendoscope, has revolutionized the diagnosis and treatment of gastrointestinal diseases that affect the submucosa, deep bowel wall, and adjacent extramural structures. This article reviews the role of endoscopic ultrasound in the diagnosis and treatment of gastrointestinal disease, including standard and promising new applications, as well as standard and emerging new technology.

Micro-lymph node metastasis and its correlation with cathepsin D expression in early gastric cancer

BACKGROUND AND OBJECTIVES

Limited operations for early gastric cancer (EGC) have been recommended based on data from lymph node (LN) metastasis detected by hematoxylin and eosin (HE) staining. Recently, the clinical importance of micro-LN metastasis has been reported. In this study, the indication of limited operations for EGC was re-evaluated based on the data from micro-LN metastasis detected by cytokeratin (CK) immunostaining. Also, the correlation between micro-LN metastasis and lysosomal acidic protease cathepsin D (CD) expression in primary tumors was evaluated.

METHODS

A total of 5,949 LNs from 160 patients with EGC were stained by anti-CK monoclonal antibody (CAM 5.2). Also, the 160 primary EGCs were stained by CD.

RESULTS

The incidence of LN metastasis increased from 7.5% (12/160) by HE-staining to 27.5% (44 of 160) by CK immunostaining. The incidence of micro-LN metastasis increased according to the depth of tumor invasion (mucosal cancer: 19% and submucosal cancer: 36.8%) and the size of tumors (< or = 1.0 cm: 5.9%, 1.1-2.0 cm: 25.6%, and > 2.1 cm: 31.7%). The CK-staining patterns were classified into the three subgroups (CK-negative, n = 116; single cell type, n = 27; and clustered type, n = 17). The occurrence of cancer recurrence was significantly higher in clustered type (17.6%) than in single cell type (3.7%) and in CK-negative (0%, P < 0.0001). The mean percentage of CD-positive cancer cells of primary tumors in clustered type (17.2%) was significantly higher than in single cell type (12.3%) and in CK-negative (7.5%, P = 0.0036).

CONCLUSIONS

The acidic protease CD may play an important role of cancer metastasis in EGC. The limited operation without lymphadenectomy should be indicated for EGC with CD-negative.

Interventional procedures

During the past year, numerous articles were published on interventional procedures of the stomach, focusing on upper gastrointestinal tract bleeding, gastric cancer, gastric outlet obstruction, and benign disease. In the area of upper gastrointestinal tract bleeding, early endoscopy is warranted for early therapeutic intervention and for triage. In patients with bleeding related to peptic ulcer disease, combination therapy (epinephrine injection in conjunction with electrocoagulation therapy) remains the standard of care. Hemoclipping is a new technique that may be helpful in cases in which conventional therapy fails. Repeat endoscopy should always be considered in patients in whom the first attempt at endoscopic therapy fails. In patients with bleeding related to portal hypertension, prophylactic antibiotics may decrease the risk of infections. Banding remains the therapy of choice for this group of patients. There is no documented benefit for combination therapy (banding and sclerotherapy). Transjugular intrahepatic portosystemic shunts may be helpful in the treatment of hypertensive portal gastropathy but not gastric vascular ectasias. In the area of gastric cancer, management revolves around staging. This can be accomplished best through the use of CT scan and endoscopic ultrasound. In patients with early limited disease, attempt at endoscopic mucosal resection should be considered. This technique can be performed in a variety of ways: the most common method seems to be through the use of a saline injection, to separate the mucosa-submucosal layer, followed by a cap-assisted snare resection with suction. The safety, efficacy, and outcome of this technique are reviewed. Gastric outlet obstruction remains a difficult problem to treat endoscopically. However, there is some evidence that endoscopic therapy may be successful in benign disease and should be considered prior to surgical intervention.