British Society of Gastroenterology guidelines on the diagnosis and management of patients at risk of gastric adenocarcinoma

Abstract

Gastric adenocarcinoma carries a poor prognosis, in part due to the late stage of diagnosis. Risk factors include Helicobacter pylori infection, family history of gastric cancer-in particular, hereditary diffuse gastric cancer and pernicious anaemia. The stages in the progression to cancer include chronic gastritis, gastric atrophy (GA), gastric intestinal metaplasia (GIM) and dysplasia. The key to early detection of cancer and improved survival is to non-invasively identify those at risk before endoscopy. However, although biomarkers may help in the detection of patients with chronic atrophic gastritis, there is insufficient evidence to support their use for population screening. High-quality endoscopy with full mucosal visualisation is an important part of improving early detection. Image-enhanced endoscopy combined with biopsy sampling for histopathology is the best approach to detect and accurately risk-stratify GA and GIM. Biopsies following the Sydney protocol from the antrum, incisura, lesser and greater curvature allow both diagnostic confirmation and risk stratification for progression to cancer. Ideally biopsies should be directed to areas of GA or GIM visualised by high-quality endoscopy. There is insufficient evidence to support screening in a low-risk population (undergoing routine diagnostic oesophagogastroduodenoscopy) such as the UK, but endoscopic surveillance every 3 years should be offered to patients with extensive GA or GIM. Endoscopic mucosal resection or endoscopic submucosal dissection of visible gastric dysplasia and early cancer has been shown to be efficacious with a high success rate and low rate of recurrence, providing that specific quality criteria are met.

Keywords: endoscopy; gastric adenocarcinoma; gastric pre-cancer; gastritis; helicobacter pylori-gastritis.

Figure 1

(A) British Society of Gastroenterology (BSG) guidelines for the endoscopic management of chronic atrophic gastritis. (B) BSG guidelines for the endoscopic management of gastric dysplasia. (C) BSG guidelines for the endoscopic management of gastric epithelial polyps. CAG, chronic atrophic gastritis; FAP, familial adenomatous polyposis; FGP, fundic gland polyp; GIM, gastric intestinal metaplasia.

Figure 2

Systematic screening protocol for the stomach. This is a station-based approach whereby each area of the stomach is viewed and photographed in either a clockwise or counterclockwise manner. The 22 pictures are arranged according to the order of the procedure. Q, quadrant; L, lesser curvature; A, anterior wall; G, greater curvature; P, posterior wall; SSS, systematic screening protocol for the somach.

Figure 3

Normal gastric corpus and antrum mucosal surface pattern with white light, enhanced and magnification endoscopy. The round ‘pit patterns’ of the corpus (Ai) and elongated ‘pit patterns’ of the antrum (Di) can be seen without magnification or enhancement. In the corpus (Ai), the red collecting venules (CV) are evident as well as the round dark red crypt openings (CO). The vascular anatomy becomes more pronounced with NBI (Aii & Dii). The visible anatomical components seen on magnification NBI include the dark brown ‘crypt openings’ (CO), the dark brown sub-epithelial capillary network (SECN), and the light brown marginal crypt epithelia (MCE). The corpus mucosa has dark round ‘crypt openings’, surrounded by the lighter MCE, followed by the darker circular SECN (Aii & Aiii). In contrast, the dark, oblique ‘crypt openings’ in the antrum are grooved so the light coloured ridged or villiform epithelium (MCE) surrounds the dark SECN, termed the ‘groove type pattern’ (Dii & Diii). The corresponding histopathological architecture can be seen in the corpus (B and C) and in the antrum (E and F).

Figure 4

Chronic atrophic gastritis (CAG) and the atrophic border on white light and image enhanced endoscopy. There are four principle endoscopic features of CAG: palor (A, B, C, D and E), loss of gastric folds (A, B, C, D and E), prominence of the vessels (A, B, C and D) and the atrophic border (A and B). The paler areas of atrophy are also clear on image enhancement (F).

Figure 5

The Integrated and Modified Kimura & Sydney Biopsy System. The modified Kimura staging system divides the extent of atrophy into antrum only (antral), antrum to incisura (antral dominant), antrum to lesser curve (corpus dominant), and antrum, lesser curve and greater curve (pan-atrophy). This system integrates Sydney protocol biopsies which should be taken from the antrum (site 1 and 2), incisura (site 3), lesser curve (site 4) and greater curve (site 5). The anatomical CAG boundaries and biopsy sites can be seen in the splayed (A) and cross-sectional cartoon (B) of the stomach. The biopsy sites defined in the endoscopic retroflexed (C) and forward view (D).

Figure 6

Gastric intestinal metaplasia under white light, image enhanced and magnification endoscopy. Intestinal metaplasia typically appears as small grey-white slightly elevated plaques surrounded by mixed patchy pink and pale areas of mucosa causing an irregular uneven surface (A). These appearances are more evident with image enhancement (B). Corpus GIM can be distinguished from the normal straight/tubular glands of the corpus by a ‘groove type pattern’ similar to that of the antrum or villiform pattern of the intestine and may be appreciated with higher resolution technology on white light endoscopy (C). GIM in the antrum is more difficult to characterize as the normal glands are oblique. Additional features of GIM to aid diagnosis in the antrum include the light blue crest (LBC) and the marginal turbid band (MTB) (D). The LBC is a fine, blue-white line on the crest of the epithelial surface seen with NBI enhancement (Fine arrows in D). The MTD can be seen between the broad arrows. The numerous goblet cells characterise GIM (E & F).

Figure 7

Fundic glandular and hyperplastic polyps. A) Fundic glandular polyps seen in the corpus and body. They are either lighter or the same colour as the surrounding mucosa. B) On near view, with image enhancement, lacy blood vessels are seen through the translucent surface and the surface shows a pattern of fine grey dots. C) Hyperplastic polyps are smooth, red buttered with whitish exudates (fibrin) and are dome shaped. The surface vascular pattern is more prominent on image enhancement (D).