Adenocarcinoma of the esophagogastric junction: could the characteristics of adjacent intestinal metaplasia help in the understanding of biopathogenesis?

Does short-segment columnar-lined esophagus elongate during a mean follow-up period of 5.7 years?

BACKGROUND

The length of Barrett's esophagus is considered to be important because it is associated with the risk of neoplasia. In Japan, there is a high prevalence of short-segment columnar-lined esophagus (SS-CLE). The natural history of SS-CLE is not fully understood, so the aim of the present study was to investigate the chronological changes of SS-CLE.

METHODS

The subjects were 500 consecutive patients with SS-CLE (327 men and 173 women; mean age: 64.0 years) diagnosed between January 2001 and July 2002 at our hospital based on the definition of SS-CLE proposed by the Japanese Society for Esophageal Diseases. Follow-up endoscopy was carried out annually for a mean period of 5.7 ± 1.2 years. The cumulative probability of SS-CLE showing elongation was estimated by the Kaplan-Meier method, and factors related to endoscopic findings making an independent contribution to elongation were determined with Cox's proportional hazard model.

RESULTS

Elongation of SS-CLE occurred in 29 patients (5.8%) during the follow-up period and the cumulative 5-year probability of elongation was 16.6%. There was no progression of SS-CLE to Barrett's adenocarcinoma. The absence of atrophic gastritis (adjusted odds ratio (aOR): 23.4; 95%CI [6.5, 83.8]), the presence of reflux esophagitis (aOR: 4.53; 95%CI [1.2, 16.4]), and the flame-shaped type of SS-CLE (aOR: 22.4; 95%CI [7.8, 64.0]) were found to be independent contributors to the elongation of SS-CLE.

CONCLUSIONS

The present study demonstrated that SS-CLE remains stable in length over time, especially in patients without atrophic gastritis, as well as in those with reflux esophagitis and/or flame-shaped SS-CLE at initial examination.

Update on the diagnosis and treatment of Barrett esophagus and related neoplastic precursor lesions

CONTEXT

At present, Barrett esophagus is the most common cause of esophageal adenocarcinoma. In the past 20 years, the incidence of esophageal adenocarcinoma in white males has exceeded that of tumors of the colorectum, lung, prostate, and skin.

OBJECTIVES

To (1) provide an evidence-based review of the diagnosis, classification, and histologic differentiation of Barrett esophagus from gastric carditis, (2) provide a summary of the key pathologic features of precursor lesions, such as dysplasia, and (3) evaluate adjunctive markers of dysplasia and predictive markers for the development of cancer. The natural history and risk of cancer in patients with Barrett esophagus is also reviewed.

DATA SOURCES

For this review, selected published peer reviewed articles were chosen from a search through PubMed between the years 1970 and 2007.

CONCLUSIONS

The current definition of Barrett esophagus is partially flawed because not all cases are endoscopically recognizable, nongoblet epithelium is biologically intestinalized, and determination of the presence or absence of goblet cells is susceptible to sampling error. Differentiation of ultrashort segment Barrett esophagus from chronic gastric carditis can be accomplished, in a minority of cases, by evaluating for the presence or absence of histologic features that are known to be associated with Barrett esophagus. Dysplasia in Barrett esophagus begins in the crypt bases and then extends more superficially to include the upper portions of the crypts and surface epithelium. Low- and high-grade dysplasia are distinguished by the presence of marked cytologic and/or architectural abnormalities in the latter compared with the former. There are few, if any, reliable adjunctive diagnostic techniques that can help differentiate nondysplastic from dysplastic epithelium. However, alpha-methylacyl coenzyme A racemase staining has been shown to be useful in 2 separate studies. Both low- and high-grade dysplasia are progressive lesions, and in general, the extent of dysplasia, particularly low grade, is a strong risk factor for progression to carcinoma. Of all the biologic and genetic biomarkers studied to date, evaluation of DNA content is the most reliable and specific. The management of patients with dysplasia is variable among institutions and ranges from aggressive surveillance, endoscopic mucosal resection, mucosal ablation, or total esophagectomy.

The histopathologic spectrum of carcinomas involving the gastroesophageal junction in the Chinese

Carcinomas involving the gastroesophageal junction are common in China. The histopathologic characteristics of these cancers have not been systematically investigated. Reported are 41 such resected cancers from Chinese patients (30 men, 11 women). Their mean age was 62 years. The mean tumor size was 4.4 cm (range, 2 to 9 cm), and 58% were poorly differentiated. An unusual spectrum of tumor differentiation was observed, including adenocarcinomas (83%), adenosquamous (32%), colloid (2%), signet-ring (10%), squamous (5%), oncocytic (7%), pancreatic acinar (12%), and neuroendocrine (5%) carcinomas. Cancers with multiple types of differentiation in the same tumor were identified in 37 cases (90%). The adjacent gastric cardiac mucosa showed hyperplasia, oncocytic, and pancreatic acinar metaplasia, and mild chronic inflammation. Dysplasia was uncommon (n = 6). Barrett esophagus was not identified. Carcinomas involving the gastroesophageal junction in the Chinese are morphologically distinct, heterogeneous, and may be of esophageal origin.

Pathologic Risk Factors of Adenocarcinoma of the Gastric Cardia and Gastroesophageal Junction

Available evidence supports the existence of two major pathways of neoplastic development in the gastroesophageal region: the Barrett pathway, related to gastroesophageal reflux disease, and the gastric pathway, related to Helicobacter pylori infection. The existence of an independent junctional pathway is questionable, and gastroesophageal junction adenocarcinomas share features of esophageal and gastric adenocarcinomas. It has been impossible to accommodate all data that are provided by different levels and tools of observation in tumors that develop in the gastroesophageal region in a single, coherent classification. That is why the stratification of pathologic risk in such tumors, and their respective precursors, incorporates features from topography, histology, immunohistochemistry, and molecular pathology.

Unraveling the mystery of the gastroesophageal junction: a pathologist's perspective

The gastroesophageal junction (GEJ), which is defined as the point where the distal esophagus joins the proximal stomach (cardia), is a short anatomic area that is commonly exposed to the injurious effects of GERD and/or Helicobacter pylori infection. These disorders often lead to inflammation and intestinal metaplasia (IM) of this anatomic region. The true gastric cardia is an extremely short segment (<0.4 mm) of mucosa that is typically composed of pure mucous glands, or mixed mucous/oxyntic glands that are histologically indistinguishable from metaplastic mucinous columnar epithelium of the distal esophagus. In patients with GERD, whether physiologic or pathologic, the length of cardia-type epithelium increases and extends proximally above the level of the anatomic GEJ into the distal esophagus. Columnar metaplasia of the distal esophagus represents a squamous to columnar metaplastic reaction that develops from an esophageal stem cell and may pass through an intermediate phase characterized by the presence of a type of epithelium that possesses a mixture of squamous and columnar features, termed multilayered epithelium. In contrast, IM of the gastric cardia represents a columnar to columnar cell metaplastic reaction that develops from a gastric stem cell located in the deep foveolar compartment of the gastric mucosa. Intestinal metaplasia, particularly the incomplete type, is widely believed to represent the precursor lesion upon which dysplasia and cancer arises. The frequency of IM is probably greater in metaplastic columnar epithelium in the esophagus secondary to GERD, than in cases of true gastric carditis secondary to H. pylori, and may be a reason why there is a higher risk of carcinoma in the former compared to the latter. A variety of clinical, endoscopic, histologic, and histochemical methods can be used to distinguish GERD-induced columnar metaplasia of the distal esophagus from H. pylori-induced inflammation of true gastric cardia, and these are outlined in this review, but further controlled studies are needed to critically evaluate these techniques. Further prospective trials are needed to adequately evaluate the different etiologic and pathogenetic mechanisms and, most importantly, the risk of malignancy in these two conditions.