Endoscopic grading of gastric intestinal metaplasia (EGGIM): a multicenter validation study

Abstract

Background Random biopsies are recommended to identify individuals at risk of gastric adenocarcinoma. Cumulative evidence suggests that narrow-band imaging (NBI) can be used to grade gastric intestinal metaplasia (GIM). We aimed to externally validate a classification of endoscopic grading of gastric intestinal metaplasia (EGGIM). Methods Consecutive patients in two centers were submitted to high resolution white-light gastroscopy followed by NBI to estimate EGGIM – a score (0 – 10) resulting from the sum of endoscopic assessments of GIM, scored as 0, 1, or 2 for no GIM, ≤ 30 %, or > 30 % of the mucosa, respectively, in five areas (lesser and greater curvature of both antrum and corpus, and incisura). If GIM was endoscopically suspected, targeted biopsies were performed; if GIM was not noticeable, random biopsies were performed according to the Sydney system to estimate the operative link on gastric intestinal metaplasia (OLGIM; the gold standard). Results 250 patients (62 % female; median age 55 years) were included. GIM was staged as OLGIM 0, I, II, III, IV in 136 (54 %), 15 (6 %), 52 (21 %), 34 (14 %), and 13 (5 %) patients, respectively. All patients with GIM except three were identifiable with targeted biopsies. For the diagnosis of OLGIM III/IV, the area under the ROC curve was 0.96 (95 % confidence interval [CI] 0.93 – 0.98) and by using the cutoff > 4, sensitivity, specificity, and positive likelihood ratio were 89 %, 95 %, and 16.5, respectively; results were similar (91 %, 95 %, and 18.1) when excluding patients with foveolar hyperplasia. Conclusions For the first time, an endoscopic approach was externally validated to determine the risk of gastric cancer without the need for biopsies. This can be used to simplify and individualize the management of patients with gastric precancerous conditions.

Helicobacter pylorieradication improved the Kyoto classification score on endoscopy

“…Villous appearance, whitish mucosa, and rough mucosal surface are helpful indicators for the endoscopic diagnosis of intestinal metaplasia. 32,33 Intestinal metaplasia score of 0 was defined as the absence of intestinal metaplasia, 1 as the presence of intestinal metaplasia within the antrum, and 2 as intestinal metaplasia extending into the corpus. Intestinal metaplasia score is calculated based on the diagnosis established using white-light imaging.…”

Where should gastric biopsies be performed when areas of intestinal metaplasia are observed?

“…It has been previously reported that in the absence of a typical pattern of IM by NBI, the predictive negative value for extensive IM is excellent independent of prevalence of IM [3,5]. In this context, we believe that random biopsies to confirm absence of preneoplastic conditions could be spared unless testing for Hp status is indicated.…”

“…For diagnosis (patient not previously known to have IM), NBItargeted biopsies should be taken in separate vials from each location (antrum/incisura and corpus) to identify individuals at high risk. The exception could be in countries with IM prevalence > 25 %, where EGGIM positive predictive value for extensive IM is ≥ 85 % and, therefore, in theory biopsies could be avoided [5]. However, in our opinion, in most diagnostic cases, biopsies from the more representative areas in the antrum and in the corpus should be taken in separate vials to also confirm the histological diagnosis.…”

“…On the other hand, Hp infection does not seem to affect this endoscopic staging system although Hp status should be investigated because these patients probably will benefit most from eradication [5]. In our personal experience, NBI-targeted biopsies from IM suspected areas will probably be enough for detection of Hp status and no additional biopsy from normal area will be needed, because targeted biopsy nearly always includes normal mucosa.…”

“…the mucosa, this approach is being increasingly questioned and the possibility of replacing random with targeted biopsies is being suggested more and more. In this context, a new endoscopic classification of IM (Endoscopic Grading of Gastric Intestinal Metaplasia [EGGIM classification]) was proposed by our group, and recently validated in a multicenter study, showing a sensitivity of 89.4 % for identifying extensive IM (OLGIM III/ IV) if EGGIM > 4 and > 99 % accuracy for excluding advance stages of gastritis if EGGIM 0 [5]. In fact, the MAPS II guideline recommends that whenever possible, virtual CE be used to target biopsies instead of performing random biopsies [1].…”