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AGA issues new guidelines on management of gastric intestinal metaplasia
The American Gastroenterological Association released new clinical practice guidelines for the management of gastric intestinal metaplasia.
Samir Gupta, MD, MSCS, AGAF, of Moores Cancer Center at University of California, San Diego, told Healio Gastroenterology and Liver Disease that the AGA’s technical review team found that approximately 5% of individuals who have a gastric biopsy in the United States will receive a diagnosis of gastric intestinal metaplasia (GIM). However, many questions persist about the management of this condition.
“The main concern is that we think it’s a risk factor for development of stomach cancer,” he said. “It’s one of the changes that occurs on the pathway to developing stomach cancer.”
Gupta said there is still a lot of variation in practice for how each individual gastroenterologist handles GIM, including different approaches to Helicobacter pylori eradication and endoscopic surveillance.
“That’s part of the void we are trying to fill and give some clarity on what people should be thinking about,” he said.
The guidelines included three recommendations:
Test for H. pylori followed by eradication over no testing and eradication
The most common population at risk for GIM is patients who have had H. pylori infection. Although research has shown that eradicating H. pylori reduces the risk for gastric cancer, Gupta said some studies have suggested that once a patient has developed GIM due to H. pylori, that eradicating it may not matter.
“That patient has gotten to a point of no return in terms of subsequent risk for stomach cancer,” Gupta said of this line of thinking. “However, on balance, when we looked at the literature, for patients with H. pylori overall and what was available for patients with GIM, the data suggest that eradicating H. pylori is favored over no testing and eradication. If someone finds GIM, we should make sure that were testing for H. Pylori, and if it is present, that we eradicate it.”
Suggest against routine use of endoscopic surveillance
The technical review team did not find much evidence in support for or against routine endoscopic surveillance. However, Gupta said the technical review team identified risk factors associated with higher risk for gastric cancer among patients with GIM who might benefit from surveillance, including those with family history of gastric cancer and specific histologic features of GIM — like extensive versus limited extent. Patients with overall increased risk for gastric cancer, such as racial or ethnic minorities, as well as immigrants from regions with high incidence could also be candidates for surveillance.
“We did identify some patients with GIM who appear to be at higher risk for gastric cancer,” Gupta said. “We think for patients with any of those characteristics there should be a shared decision making that goes on with the doctor and the patient that could lead to a recommendation for surveillance.”
Suggest against routine short-interval, repeat endoscopy
While some GIs routinely perform repeat endoscopy for risk stratification in patients with GIM, Gupta said that may not be necessary for all patients.
“Our conclusion was that if the patient already has a risk feature that might increase the risk for stomach cancer, you might not need to do a short-interval repeat endoscopy within 12 months,” he said. “You might already have the information you need to have that informed conversation with the patient about whether they want to do subsequent surveillance.” – by Alex Young
Disclosure: The authors report no relevant financial disclosures.
Perspective
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This revolves around the idea of who really benefits from gastric cancer screening. Globally, that question has a different answer depending on where you are. Gastric cancer is the fifth most common cancer in the world. It’s also third regarding cancer-related mortality because most gastric cancers are diagnosed at late stage.
Overall survival at 5 years is approximately 30% for patients diagnosed with advanced stage gastric cancer. However, if you detect early cancerous lesions the survival is much better. Five-year overall survival is greater than 90% when it is detected early.
It has always been believed that the best way to attack gastric cancer is early detection and early treatment. In countries with a high gastric cancer incidence, Korea and Japan for example, that statement is true. There are national screening programs in Korea where patients undergo upper endoscopy every 2 years. That has led to most gastric cancers diagnosed at an early stage with an approximate 40% relative risk reduction in gastric cancer mortality.
The problem is that in the U.S., gastric cancer is not our fifth most common cancer, but rather the 14th most common. There are only 55,000 cases per year in the U.S., so the idea of mass screening with an upper endoscopy does not make fundamental sense.
The question then becomes, are there high-risk populations within the U.S. that can potentially benefit from screening? One of the controversies that has always come up is that intestinal metaplasia is quite common to encounter and what do we do about it?
The AGA’s guidelines are in line with those that have previously come out from ASGE and MAPS 2. I think that helps give some consistency.
It comes down to, when you see gastrointestinal metaplasia on a scope, what do you do? Do you let the patient go, do you send them off for surveillance, or if you don’t send them to surveillance, are you doing the wrong thing for the patient? The guidelines very clearly state that there’s not enough evidence to suggest for routine endoscopic surveillance, but they did say for certain patients who are at a higher risk there is that potential for discussion with the patient about having surveillance moving forward.
There are some features additional to intestinal metaplasia that might make patients feel they may benefit from surveillance.
There are two types of gastrointestinal metaplasia, incomplete vs. complete gastrointestinal metaplasia. When someone goes from normal gastric mucosa to intestinal metaplasia, there is a complete form that has a complete set of enzymes, called complete intestinal metaplasia and there’s an incomplete form where it doesn’t have all the digestive enzymes and that’s called incomplete or colonic form. While incomplete intestinal metaplasia is believed to be a higher risk entity, most labs in the United States do not routinely test or differentiate between complete and incomplete GIM. This is something specifically that you would have to ask your pathologist to be able to do that testing. The difference between the idea of intensive and limited gastrointestinal metaplasia is also interesting because you would need to take multiple biopsies throughout the stomach to determine if it is limited or extensive and that’s not always done on surveillance or screening endoscopy.
Another thing to point out from these guidelines was that gastrointestinal metaplasia shouldn’t be all about surveillance or screening but treating H. pylori is important. Patients with GIM should be tested and treated for H. pylori if positive, and then the treating physician should confirm that the H. pylori has been eradicated. That’s probably the number one thing that we can do to intervene and reduce the risk for gastric cancer.
These guidelines will help U.S. physicians. Gastrointestinal metaplasia is something commonly encountered, but I think it is something people feel uncomfortable about because there have not been really clear guidelines before about having discussions with patients and what to do. This guideline gives us an option to tell patients who are low risk that the risk is low, and if patients are concerned, have family history or a certain ethnic background, then physicians can talk with them about surveillance programs. It’s good for our physicians and patients moving forward and helps simplify the management of patients.
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