This transcript has been edited for clarity.
Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School. Welcome back to another GI Common Concerns.
Today, I want to talk about the management of gastric intestinal metaplasia (GIM). It's something that we commonly see on biopsies yet likely have incredibly disparate ideas about how to best manage. There are several aspects to this that we can improve.
Progression to GIM and Beyond
Gastric cancer is the third leading cause of cancer-related death in the world, accounting for over a million incident cancers annually and 26,000-plus cancers in the United States alone. The majority of these cases are what we typically call noncardia gastric cancers arising from the antrum, the fundus, the incisura, and the body. This is most often caused by chronic Helicobacter pylori infection.
These noncardia intestinal-type gastric cancers follow a stepwise progression known as the Correa cascade. This progression goes from normal mucosa to gastritis, nonatrophic gastritis, atrophic gastritis, GIM, and then gastric adenocarcinoma.
The ability to follow patients with GIM and strategize for them accordingly is the focus of today's discussion.
There's tremendous variation in the practice patterns of physicians regarding the biopsy and management of GIM. This is particularly true in the United States, especially among centers that may see a higher volume of patients with relative risk factors for GIM, such as racial-, ethnic-, or immigration-related factors.
We can address this variance, however, by identifying the things that we're probably not doing well at the moment, reviewing guidelines from the American Gastroenterological Association (AGA), and then focusing on how we can do better.
Areas for Improvement
Biopsy technique is the first thing we're probably not doing correctly when it comes to GIM.
The Sydney protocol involves a biopsy approach of two separate areas. Biopsy bottle number 1 consists of routine biopsies in the antrum, lesser curvature, greater curvature, and the incisura, the latter of which seems to have a higher incidence of GIM and progression to dysplasia. Biopsy bottle number 2 is in the corpus — in particular, in the lesser curvature and greater curvature. Here, any focal lesion gets a separate biopsy. It's very analogous to what we would do in our surveillance strategies with Barrett's esophagus.
The second thing we're not doing well in GIM is classification by the histopathologist, where I think we're really falling off quite dramatically.
There are two instruments used for histopathologic assessment that can portend greater risk for progression: the operative link on gastritis assessment (OLGA) and the operative link on gastric intestinal metaplasia assessment (OLGIM) staging systems. These are validated instruments that the histopathologist could easily follow, which rate different stages according to the combined biopsies of the antrum and fundus. The level of involvement goes from 0 to 3 in the score, and then the relative combined score of the antrum and fundus gets a total from 0 to 4.
The staging from 3 to 4 is very important because it has been associated with increased risk for gastric cancer-about a 21-fold greater odds. Gastric cancer can also progress rapidly in patients with scores in the 3-4 score range, typically in less than 2 years.
Therefore, it's important to get the histopathologist to identify the OLGA/OLGIM for us. These are very routine histologic assessments based on standard criteria, each of which requires no special stains. But the histologic/pathologic implications, I think, are very important and warrant speaking with your pathologist so they can incorporate them.
Following the Guidelines
The next thing to consider is how to apply the latest GIM guidelines.
In December 2019, the AGA released guidelines around the management of GIM, which accompanied two separate, very intensely researched technical reviews on the topics of natural history/clinical outcomes and epidemiology/risk factors, which I thought were brilliant.
The first AGA guideline recommendation with GIM is, obviously, to treat H pylori and document its eradication.
The authors did not recommend routine use of endoscopic surveillance in patients with GIM. The possible exception is after having an informed discussion with the patient, particularly if they're at high risk, which is classified histologically as incomplete vs complete. Incomplete is more of the colonic type of GIM, whereas complete is more the small-intestinal type, which relates to brush border and goblet cells and is beyond the scope of today's discussion.
Another determinant of high-risk status is whether the GIM is extensive vs limited. Going back to those two biopsy bottles, GIM is extensive if it's evident in both samples taken from the body, whereas it's limited if found in just one of the samples. Extensive [GIM], obviously, would lead to a higher-risk profile.
Other factors contributing to high-risk status are family history, certain racial or ethnic minorities, and migration from areas with a high-incidence GIM. Those patients potentially require an individualized discussion and a return visit for more intense evaluation.
The third AGA guideline recommendation is that when you identify GIM, in the absence of visually detected abnormalities, you don't need to bring these patients back early.
This is in line with certain other guidelines. In 2015, the American Society for Gastrointestinal Endoscopy published guidelines recommending that patients with GIM and two sequential evaluations without progression or dysplasia could be disenrolled from surveillance. This is similar to endoscopy recommendations from the AGA as well as from the European Society of Gastrointestinal Endoscopy, which noted you should not necessarily have to bring these people back, except if they had the higher stage of 3 to 4 on the OLGA/OLGIM. Those patients should be individualized and perhaps be brought back more routinely, even at a 1-year interval.
Routine endoscopic surveillance is likely unnecessary in the vast majority of patients.
Immediate Steps for Managing GIM
In terms of how we can do better now, I'd like to draw your attention to an excellent training piece by Shah and colleagues published in Gastroenterology. This offers some key pieces of advice worth highlighting.
Starting at pre-endoscopy, we have to recognize who's at risk. Before you scope your patient, look at their age, ethnicity, birth country, H pylori infection, and lifestyle factors like smoking, and family history. Weighing these factors will allow you to consider whether you need to obtain a biopsy.
The endoscopic features of GIM are something you also need to consider. It's particularly important to set your mind to this before you get into the procedure by ensuring you're using the appropriate equipment. At a minimum, this would be high-definition white-light endoscopy with advanced imaging (eg, narrow-band imaging). Learn the endoscopic appearance of both white-light and the other advanced imaging technique for a development of focality for GIM.
Then, make sure you have adequate visualization. It's analogous to what we do in the colon: wash, wash, wash. Get all the debris out. If you need to have bubbles removed, use a mucosal-clearance agent like simethicone. Make sure you adequately distend and insufflate all the folds. The authors make a point of using a dwell time of 6-7 minutes, much like we use for withdrawal times in the colon, where more is better.
Make sure you adequately describe what you see in your endoscopic report. Histologic analysis is really predicated on where you got the biopsies from, so you should photo-document these as well.
Ensure that the biopsy is obtained using the Sydney protocol, which requires samples from the antrum (times three), greater curvature, lesser curvature, and the incisura, as well as the lesser curvature and greater curvature of the corpus. Samples from any concerning lesions are kept in separate bottles.
After endoscopy, focus on histologic confirmation. This requires talking to your pathologists about using the OLGA/OGLIM criteria for risk stratification, which allows us to decide whether these patients can be disenrolled [from surveillance] or need to return with some periodicity.
Treat H pylori. Obviously, that's a no brainer. Document successful eradication.
If you apply this risk-based approach to your identification of GIM, you will be able to dismiss a lot of these patients with reassurance that they really aren't at higher risk for gastric cancer.
I suspect we can all look at ourselves and know we can do better. GIM is common. We need to up the ante for how we can improve the management of patients with GIM.
I hope you find this helpful the next time you face a patient with GIM.
I'm Dr David Johnson. Thanks again for listening. See you next time.
David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.
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Cite this: A Guide to Managing Gastric Intestinal Metaplasia - Medscape - Jan 19, 2023.