Introduction

This chapter focuses on clinical gastroenterology issues of interest to pathologists, including endoscopic diagnosis and management of Barrett esophagus, management of intestinal metaplasia in the setting of chronic gastritis, and surveillance in patients with inflammatory bowel disease, colonic polyps, and colon cancer.

Surveillance in Patients with Barrett Esophagus

Most authorities recommend that patients with chronic reflux symptoms lasting 5 or more years undergo an upper endoscopy to screen for Barrett esophagus (Table 2.1). The benefits of screening programs for Barrett esophagus are controversial because of a lack of sufficient evidence that such programs improve survival rates or are cost-effective.¹ Furthermore, there is only indirect evidence to suggest that patients diagnosed with adenocarcinoma while undergoing surveillance have an increased chance of survival. Nevertheless, the current standard of care dictates that if Barrett esophagus is diagnosed, the patient should be entered into an endoscopic surveillance program for early detection of dysplasia and adenocarcinoma.²

Data from Spechler SJ, Sharma P, Souza RF, et al. American Gastroenterological Association medical position statement on the management of Barrett’s esophagus. Gastroenterology. 2011;140:1084-1091.

Surveillance in Patients with Chronic Gastritis and Intestinal Metaplasia or Dysplasia

The most common causes of chronic gastritis are Helicobacter pylori infection, environmental exposures including smoking, and autoimmune processes. Biopsies obtained during endoscopy from patients with chronic gastritis may reveal intestinal metaplasia (IM). A study from the United States demonstrated that 13% of patients at low risk for gastric cancer, and 50% of patients at high risk, had IM on biopsies from normal-appearing gastric mucosa.¹¹ Although gastric IM (incomplete type) is considered a premalignant lesion, the overall risk of gastric cancer in patients with gastric IM is very low. However, patients with IM and dysplasia have an approximately 100-fold increased risk of gastric cancer.¹¹

In the United States, where the incidence of gastric cancer is low, endoscopic surveillance of patients with gastric IM is not recommended in patients who are at low risk for gastric cancer.¹¹ Low-risk patients include those living in developed countries, whites without any family history of gastric cancer, and individuals without dysplasia on gastric biopsy. The likelihood that endoscopic surveillance of low-risk patients with IM will increase detection of curable gastric cancer is very low, and therefore it is not likely to be cost-effective. Furthermore, IM is a histologic lesion that is not visible by the endoscopist. This makes endoscopic surveillance difficult, because numerous biopsies mapping the stomach would be needed to obtain a significant yield.

Surveillance in patients with IM who are at high risk for gastric cancer is controversial. High-risk patients include those with a family history of gastric cancer, Hispanics, blacks, and immigrants from higher-risk geographic locations. No formal recommendations or data exist to support the implementation of an endoscopic surveillance program in high-risk patients with gastric IM. The American Society of Gastrointestinal Endoscopy (ASGE) concluded that patients who are at increased risk for gastric cancer on the basis of ethnic background or family history may benefit from surveillance, but there was no specific recommendation on the frequency of endoscopy. If surveillance is performed, the ASGE recommended that endoscopic surveillance with gastric biopsies should incorporate a topographic mapping of the entire stomach histologically.¹²

The location and type of dysplasia found determine the surveillance guidelines for patients with IM. The histopathologic classification divides cases into the subtypes of incomplete and complete IM, a distinction best determined after assessment for and eradication of H. pylori infection. Studies have suggested that if the patient has incomplete or extensive IM, topographic mapping of the gastric mucosa should be performed at 1 year, followed by repeated surveillance endoscopy every 3 years if extensive metaplasia persists.¹³ There is no consensus regarding surveillance in LGD, but most studies suggest that surveillance is not warranted in average-risk patients.¹² The ASGE recommends that patients with confirmed HGD on gastric biopsies be considered for gastrectomy or EMR.¹¹ We expect that further recommendations regarding appropriate intervals for surveillance endoscopy and the use of new techniques will be formalized in the near future.

Pernicious anemia, which can occur as a result of autoimmune chronic atrophic gastritis, is another potential risk factor for gastric cancer and gastric carcinoid. A twofold to threefold increased risk of gastric cancer has been seen, depending on the location and duration of disease.¹⁴ Clear guidelines for surveillance in atrophic gastritis have not yet been established. Current guidelines from the ASGE advocate performance of a screening upper endoscopy at the time of diagnosis of pernicious anemia to identify lesions such a carcinoid or gastric cancer, but there are only weak data to support subsequent surveillance endoscopy if the initial test is negative.¹²

Surveillance for Colorectal Neoplasia in Patients with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which comprises ulcerative colitis (UC) and Crohn’s disease, is the second most common inflammatory disorder after rheumatoid arthritis. There are approximately 1.4 million patients with IBD in the United States.^14a Each year, between 20,000 and 25,000 new cases are diagnosed. The peak incidence occurs between the ages of 15 to 35, with males and females equally affected.

The goal of colonoscopic surveillance is to minimize the morbidity and mortality from colorectal cancer (CRC) with appropriate and timely referral for colectomy. Close interaction between endoscopist and the pathologist is crucial in the management of IBD.¹⁵ Although no prospective randomized studies have been performed to evaluate the efficacy of surveillance colonoscopy to detect dysplasia or CRC in UC patients, case-control studies suggest a reduction in mortality in those undergoing surveillance.¹⁶ Surveillance colonoscopy should optimally be performed when the patient is in clinical remission, because active inflammation may hinder the histologic diagnosis of dysplasia.

Biopsies taken during surveillance colonoscopy are graded as positive for dysplasia, negative for dysplasia, or indefinite for dysplasia. Dysplasia is further classified as LGD, HGD, or carcinoma.¹⁷ The greatest interobserver variability among pathologists lies in the interpretation of the LGD and indefinite-for-dysplasia categories. Therefore, once dysplasia is detected, a second pathologist with expertise in interpretation of gastrointestinal biopsies should confirm the diagnosis. Dysplastic mucosa may be characterized as either flat or raised. Flat dysplasia is generally considered to be endoscopically undetectable, is identified by random biopsies, and can be further classified as either multifocal or unifocal. Raised or polypoid dysplasia is referred to by the acronym DALM: dysplasia-associated lesion or mass.

Current guidelines from the American College of Gastroenterology (ACG), the American Gastroenterology Association (AGA) (Table 2.3), and the British Society of Gastroenterology(BSG) (Table 2.4) recommend that colonoscopic surveillance begin 8 to 10 years after the onset of symptoms of colitis in patients with UC or with Crohn’s colitis involving at least one third of the colon.^18–20 The results of the colonoscopy determine the extent of disease, and appropriate patients are then entered into a surveillance program. Repeated surveillance colonoscopy is performed every 1 to 3 years (AGA) or 1 to 5 years (BSG).¹⁸ Patients with coexisting primary sclerosing cholangitis should begin surveillance colonoscopy at the time of diagnosis of liver disease and continue annually thereafter regardless of the extent of disease. Other risk factors associated with an increased risk of developing colorectal neoplasia include CRC in a first-degree relative, ongoing active endoscopic or histologic inflammation, and anatomic abnormalities such as a foreshortened colon, stricture, or multiple inflammatory pseudopolyps. Several studies have correlated increased severity of colonoscopic macroscopic and histologic inflammation with a higher risk of CRC.^21,22 Male gender has been identified as a risk factor for development of CRC.^23,24 Patients with proctitis or distal proctosigmoiditis are not at increased risk for the development of CRC and do not need to undergo surveillance.

CRC, Colorectal cancer; IBD, inflammatory bowel disease; PSC, primary sclerosing cholangitis.

From Farraye FA, Odze RD, Eaden J, Itzkowitz SH. AGA technical review on the diagnosis and management of colorectal neoplasia in inflammatory bowel disease. Gastroenterology. 2010;138:746-774.e4.