Pathological appearance of the stomach after endoscopic mucosal resection for early gastric cancer

Advantages of endoscopic submucosal dissection over conventional endoscopic mucosal resection

BACKGROUND

Endoscopic mucosal resection is an established method for treating intramucosal gastric neoplasms. Conventional endoscopic mucosal resection has predominantly been performed using strip biopsy, but local recurrence sometimes occurs due to such piecemeal resection. Endoscopic submucosal dissection has recently been performed in Japan using new devices such as an insulation-tip diathermic knife. The efficacy and problems associated with endoscopic submucosal dissection were evaluated by comparison with conventional endoscopic mucosal resection.

METHODS

Treatment consisted of conventional endoscopic mucosal resection for 48 lesions from January 1999 to October 2002, and endoscopic submucosal dissection for 59 lesions from November 2002 to June 2005. Endoscopic submucosal dissection was performed using an insulation-tip diathermic knife and flex and hook knives, as appropriate.

RESULTS

For lesions >or=11 mm in size, en bloc resection rates were significantly higher with endoscopic submucosal dissection than with conventional endoscopic mucosal resection, but treatment time was significantly longer. En bloc resection rates were higher with endoscopic submucosal dissection than with conventional endoscopic mucosal resection in all areas. Treatment of lesions in the upper one-third of the stomach took a long time using endoscopic submucosal dissection, and intraoperative bleeding was frequent. However, en bloc resection rates and intraoperative bleeding with endoscopic submucosal dissection were improved using various knives.

CONCLUSIONS

Endoscopic submucosal dissection can take a long time, but is superior to conventional endoscopic mucosal resection for treating intramucosal gastric neoplasms.

Characteristics of intramucosal gastric carcinoma with lymph node metastatic disease

AIM

Recent trends in treatment strategy for early gastric cancer (EGC) are towards minimal surgical procedures, such as endoscopic mucosal resection and laparoscopic partial resection. There is a possibility of incomplete removal of regional lymph nodes in minimal procedures, which may subsequently decrease the chance of a cure. Therefore, it is essential to be able to predict lymph node status and to make careful selection of candidates for mucosal resection.

METHODS AND RESULTS

We studied the relationship between lymph node status and various pathological parameters including macroscopic appearance, location, size, differentiation, presence of ulceration, vascularity, presence of gastritis cystica profunda-like glandular proliferation, disruption of the muscularis mucosae and invasion into the muscularis mucosae, using age- and sex-matched samples of 40 node-positive and 80 node-negative tumours to define the characteristics of intramucosal EGCs. Histological differentiation (P < 0.001), increased submucosal vascularity (P < 0.05), breakdown of the muscularis mucosae (P < 0.05), and invasion of tumour cells into the muscularis mucosae (P < 0.05) were correlated with the lymph node status of intramucosal gastric carcinoma. Furthermore, diffuse type histology (P < 0.001) and deep invasion into the muscularis mucosae (P < 0.05) were indicators of node-positive intramucosal EGCs.

CONCLUSIONS

These histological indicators are easily accessible and seem to predict lymph node metastatic disease in limited surgical specimens. Patients should be carefully selected despite the recent trend toward less invasive resection of EGCs, especially for those apparently confined to the mucosa.