Stretching Causes Extensive Changes of Gastric Submucosa: Is It Acceptable to Define 500μm as the Safe Margin?

Abstract

Background/Aims: Endoscopic mucosal resection can cure early gastric cancer. The risk of lymphatic metastasis is related to the depth of submucosal invasion by the mucosal malignancy, with a resection depth of 500μm generally accepted as a safe cut-off. However, excessive thinning induced by stretching of the resected tissue sometimes preventing a precise diagnosis. We studied the effects of stretching on different layers and sites of gastric tissue. Methods: Porcine stomachs were cut into 2.0×2.0 cm pieces, and pieces from body were stretched to 2.5, 3.0, and 3.5 cm. Pieces from the cardia, body, and antrum were also stretched to 3.0 cm. The thickness of each layer was measured and analyzed statistically. Results: Whole gastric wall and submucosal layers showed gradual thinning, with stretching to 3.5 cm tearing the tissues and resulting in imperfect extension. The submucosa was thinner in body tissue than in cardia and antrum tissues. Stretching to 3.0 cm induced a consistent decrease in submucosal thickness (30-70%). The change in thickness varied widely between individual samples. Conclusions: A resection margin of 500μm might be insufficient for the complete removal of malignancy. Moreover, the thickness of the submucosal layer differs with the gastric site and between individuals. Future studies are needed to confirm the findings in human tissue.

Porcine intestinal mast cells. Evaluation of different fixatives for histochemical staining techniques considering tissue shrinkage

“…Architecturally, the mucosa is a relatively tough compartment in contrast to the underlying submucosa which is designed to act as a shifting layer between the tunica mucosa and the tunica muscularis, enabling them to move against each other, 70 possibly resulting in varying shrinkage potential for this compartment. In a study on porcine stomach submucosa an individual variation in a range from 3 to 70% of the observed morphological parameter was detected 71 . Their and our results indicate that in future studies on (mast) cell counting individual shrinkage factors for individual tissue layers may need to be determined.…”

Preprocedural prediction of non-curative endoscopic submucosal dissection for early gastric cancer

“…Therefore, EGCs located at the upper/mid third of stomach might be more easily missed or diagnosed later than those in the lower third of stomach. The thickness of the submucosa has been reported to be thinner in the body than at the antrum [17], and the lymphatic capillaries are present just above the muscularis mucosa [18]. These anatomical factors may be associated with the submucosal invasive EGC located at the upper/mid third of the stomach as an increased risk for non-curative endoscopic resection.…”

Clinico-pathologic determinants of non-e-curative outcomes following en-bloc endoscopic submucosal dissection in patients with early gastric neoplasia

“…This is because maintaining a front view of endoscopy is challenging and it has to be used in its retro exed fashion [58]. Additionally, there is a difference in thickness of submucosal layer between body and antrum, with the former being thinner as compared to the latter [59]. At last but not least, relatively abundant lymphatic vessels are found in the lamina propria of cardia region as opposed to lower regions of the stomach [60].…”