The endoscopic diagnosis of early gastric cancer

Abstract

The aim of this article is to demonstrate the basic principles for the endoscopic diagnosis of early gastric cancer. The diagnostic process can be divided into two steps, detection and characterization. Detection requires good endoscopic technique, and thorough knowledge. With regard to technique, we should administer the optimum preparation to patients, including an antiperistaltic agent. Furthermore, in order to map the entire stomach we need to follow a standardized protocol, and we propose a systematic screening protocol for the stomach. With regard to knowledge, we should be able to identify high-risk background mucosa, and we should be aware of the indicators of a suspicious lesion. Chromoendoscopy and magnifying endoscopy are promising image-enhanced endoscopic techniques for characterization. The proposed criteria for a cancerous lesion are as follows: conventional endoscopic findings of 1) a well-demarcated lesion and 2) irregularity in color/surface pattern; vessel plus surface classification using magnifying endoscopy with narrow-band imaging findings of 1) irregular microvascular pattern with a demarcation line or 2) irregular microsurface pattern with a demarcation line. Conventional endoscopy and subsequent image-enhanced endoscopy can both contribute to the detection of early gastric cancer.

Keywords: Early gastric cancer; endoscopy; image-enhanced endoscopy; magnifying endoscopy with narrow-band imaging; systematic screening of the stomach.

Conflict of interest statement

Conflict of Interest: None

Figures

Figure 1

Endoscopic findings of advanced gastric cancer on the greater curvature of the lower gastric body. (A) With insufflation of a small amount of air, the appearance is normal. (B) However, when we insufflate more air and extend the gastric wall together with the greater curvature with gastric foils, a distinct lesion, suggestive of advanced gastric cancer, becomes evident. In fact, the histopathological diagnosis of the biopsied specimen was invasive signet-ring cell carcinoma

Figure 2

Proposed SSS. The SSS should be initiated as soon as we insert the scope into the gastric antrum. With the antegrade view, we should take endoscopic photos of 4 quadrants of the gastric antrum, body and middle-upper body. Then, with the retroflex view, we take endoscopic photos of 4 quadrants of the gastric fundus and cardia, and 3 quadrants of the gastric middle-upper body and incisura. Overall, the SSS series comprises 22 endoscopic photos

Figure 3

Magnified endoscopic findings of gastric fundic gland mucosa. Observation by magnified endoscopy focusing on gastric fundic gland mucosa (fundus and body) is indeed useful for estimating the risk of gastric cancer. (A, B) Normal gastric body mucosa. The microvascular pattern shows regular honeycomb-like SECN pattern (brownish color) with RAC venules (cyan color). The microsurface pattern shows regular oval CO (brownish color) and oval MCE (whitish semitransparent part). (C) Helicobacter pylori-associated gastritis. When the gastric mucosa is accompanied with Helicobacter pylori-associated gastritis, both the microvascular and microsurface patterns show remarkable diffuse amendments compared with normal mucosa. Namely, the SECN pattern is dilated and the CV is not visualized in the inflamed mucosa, while MCE has a curved/oval shape which is different from normal morphology and CO is not visualized as a brownish pit. (D) Atrophic gastritis. When there is marked atrophy in the gastric body mucosa. The CV can be visualized again, however no honeycomb-like SECN pattern can be identified and neither MCE nor CO can be identified in remarkably atrophic mucosa. This type of appearance is also identified in autoimmune gastritis as well as common atrophic gastritis associated with Helicobacter pylori infection

Figure 4

M-NBI findings of intestinal metaplasia. We occasionally encounter the unique phenomenon called LBC at the edge of MCE when we observe chronic gastritis with Helicobacter pylori-associated gastritis by M-NBI [7]. The LBC is originally defined as fine, blue white line on the crest of the epithelial surface/gyri. This LBC is highly predictive of histological intestinal metaplasia

Figure 5

Endoscopic findings of superficial elevated (0 IIa) type early gastric cancer in the gastric antrum. Histological type: differentiated (intestinal) type. (A) Conventional white light imaging shows a slightly elevated lesion. The light reflection suggests something different in surface morphology. (B) Indigo carmine chromoendoscopy demonstrates a well-demarcated superficial elevated lesion with an irregular surface pattern

Figure 6

Endoscopic findings of superficial depressed (0 IIc) type early gastric cancer in the gastric cardia. Histological type: differentiated (intestinal) type. (A) Conventional white light imaging depicts a reddened depressed lesion with spontaneous bleeding. (B) Indigo carmine chromoendoscopy demonstrates a well-demarcated lesion with an irregular margin a well-demarcated lesion with an irregular margin

Figure 7

Endoscopic findings of superficial depressed (0 IIc) type early gastric cancer in the gastric body. Histological type: undifferentiated (diffuse) type. (A) Conventional white light imaging demonstrates a pale depressed lesion. (B) Indigo carmine chromoendoscopy delineates

Figure 8

A soft black hood is mounted on the tip of the magnifying endoscope

Figure 9

Correlation between microanatomy (lower column) and endoscopic images (upper column)

Figure 10

VS classification. Arrows show demarcation lines

Figure 11

A slightly depressed lesion in the gastric antrum (non-cancer, 5 mm). (A) C-WLI demonstrates a slightly depressed well-demarcated lesion with irregular margins (arrow). This lesion is suspicious for cancer by C-WLI alone. (B) M-NBI (VS classification) demonstrates a regular microvascular pattern and a regular microsurface pattern with a demarcation line (arrows). The M-NBI findings enable us to accurately diagnose this as a noncancerous lesion. (C) Histopathological findings of the biopsy specimen represent chronic gastritis with intestinal metaplasia

Figure 12

A slightly depressed lesion on the gastric antrum (non-cancer, 3 mm). (A) C-WLI demonstrates a slightly depressed, poorly demarcated lesion with a regular margin (arrow). This lesion is not suspicious for cancer by C-WLI alone. (B) However, examination using M-NBI demonstrates an irregular microvascular pattern and absent microsurface pattern with a clear demarcation line. According to the VS classification system, these findings meet the criteria for a cancerous lesion. (C) Histopathological findings of resected specimen by endoscopic dissection technique represent a well-differentiated adenocarcinoma confined to the mucosa

Figure 13

An early gastric cancer of superficial flat type. (A) C-WLI cannot detect the presence of a cancer, let alone the border of the cancerous lesion. (B) When we examine the marginal part of the lesion using M-NBI, we see distinct demarcation lines (arrows) and an irregular microvascular pattern and irregular microsurface pattern within the demarcation line. According to the VS classification system, this section is a border specific for cancerous mucosa. (C) Using M-NBI, we placed electrocoagulation markings on the background non-cancerous mucosa just outside the demarcation line. (D) The resected specimen with mapping of the cancerous mucosa demonstrates that the markings were correctly placed just outside the cancerous mucosa

Figure 14

A strategy for determining the lateral extent of early gastric cancer, for curative endoscopic resection

Figure 15

A superficial elevated lesion on the gastric antrum (low-grade adenoma). (A) C-WLI shows a slightly elevated well-demarcated lesion (arrow). (B) M-NBI shows that the microvascular pattern was not visualized because a dense WOS obscured the subepithelial microvascular pattern. The WOS morphology exhibits a regular maze-like pattern. According to VS classification system, the M-NBI findings are categorized as an absent microvascular pattern and regular MS pattern with a demarcation line. Hence, this lesion is diagnosed as a noncancerous lesion (low-grade adenoma)

Figure 16

A superficial elevated lesion at the gastric lower body (well-differentiated adenocarcinoma). (A) C-WLI shows a slightly elevated well-demarcated lesion (arrow). (B) M-NBI shows that the microvascular pattern was not visualized because a dense WOS obscured the subepithelial microvascular pattern. The WOS morphology exhibits an irregular speckled pattern. According to the VS classification system, the M-NBI findings are categorized as an absent microvascular pattern and irregular MS pattern with a demarcation line (arrows). Hence, this lesion is diagnosed as a cancerous lesion

Figure 17

Endoscopic findings of a microcarcinoid tumor at the greater curvature of the gastric body. (A) C-WLI shows a reddened semispherical elevated lesion. (B) M-NBI shows regular microvascular pattern and regular microsurface pattern with widened intervening parts. There is no clear demarcation line between the lesion and background mucosa

Figure 18

(A) Endoscopic findings of MALT lymphoma at the greater curvature of the gastric body. (B) C-WLI shows a slightly elevated lesion with a smooth surface

Figure 19

An endoscopic diagnostic strategy for early gastric cancer