Adenocarcinoma of the oesophago SJ Spechlerp Hainaut

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gastric junction

M.F. Dixon R. Lambert

R. Genta R. Siewert

Definition

Adenocarcinomas that straddle the junction of the oesophagus and stomach are called tumours of the oesophagogastric (OG) junction. This definition includes many tumours formerly called cancers of the gastric cardia.

Squamous cell carcinomas that occur at the OG junction are considered carcinomas of the distal oesophagus, even if they cross the OG junction.

ICD-O code 8140/3

Definition of the oesophagogastric junction

The OG junction is the anatomical region where the tubular oesophagus joins the stomach. The squamo-columnar (SC) epithelial junction may occur at or above the OG junction. The gastric cardia has been defined conceptually as the region of the stomach that adjoins the oesophagus {1568}. The gastric cardia begins at the OG junction, but its distal extent is poorly defined.

Figure 2.01 shows endoscopically recognizable landmarks that can be used to identify structures at the OG junction. The squamocolumnar junction (SCJ or Z-line) is the visible line formed by the juxtaposition of squamous and columnar epithelia. The OG junction is the imaginary line at which the oesophagus ends and the

Oesophagogastric Junction
Fig. 2.01 Topography of the oesophagogastric junction and cardia {1797}.

stomach begins anatomically. The OG junction is defined endoscopically as the level of the most proximal extent of the gastric folds {1200}. In normal individuals, the proximal extent of the gastric folds generally corresponds to the point at which the tubular oesophagus flares to become the sack-shaped stomach at the distal border of the lower oesophageal sphincter. In patients with hiatus hernias, in whom there may be no clear-cut flare at the OG junction, the proximal margin of the gastric folds is determined when the distal oesophagus is minimally inflated with air because over-inflation obscures this landmark {1271}. Whenever the squamocolumnar junction is located above the OG junction, there is a columnar-lined segment of oesophagus. When the squamocolumnar junction and the OG junction coincide, the entire oesophagus is lined by squamous epithelium (i.e. there is no columnar-lined oesophagus). By definition, the gastric cardia starts at the OG junction, but there are no endoscopic landmarks that define the distal extent of the gastric cardia.

A potential source of confusion is the his-tological terminology used to describe the most proximal part of the stomach. Cardiac mucosa is characterized by tortuous, tubular glands that are comprised almost exclusively of mucus-secreting cells with few or no parietal (oxyntic) cells. The histological finding of cardiac mucosa does not establish that the specimen has been obtained from the cardia of the stomach, for the following reasons:

(1) Cardiac mucosa can be found in the distal oesophagus {1479, 678}.

(2) Cardiac mucosa rarely extends more than 2 to 3 mm below the SC epithelial junction in the distal oesophagus {1430, 911}. Therefore it will not line the larger anatomical area often called cardia.

(3) Recent studies have shown that the proximal stomach is lined predominantly, if not exclusively, by oxyntic epithelium {272, 1388}. Therefore, even a tumour that is unquestionably located at the cardia may not have arisen from cardiac epithe lium. Conversely, a tumour that clearly is located in the distal oesophagus could have arisen from oesophageal cardiac epithelium.

Some investigators actually contend that cardiac mucosa is not a normal mucosa at all, but one that is acquired as a consequence of chronic inflammation in the distal oesophagus {272, 1388}.

Diagnostic criteria

Various criteria have been used to categorize tumours in the region of the OG junction as cancers of the gastric cardia {1240, 314, 877, 1271, 638, 767, 684}. In most of these classification systems, the anatomic location of the epicenter or predominant mass of the tumour is used to determine whether the neoplasm is oesophageal or gastric in origin. Due to the use of divergent classification systems, the patient populations in studies on cancers of the gastric cardia are heterogeneous, and often include patients with gastric tumours and others with tumours of oesophageal origin. The following guidelines are based on the definition of the OG junction described above:

(1) Adenocarcinomas that cross the oesophagogastric junction are called adenocarcinomas of the OG junction, regardless of where the bulk of the tumour lies.

(2) Adenocarcinomas located entirely above the oesophagogastric junction as defined above are considered oeso-phageal carcinomas.

(3) Adenocarcinomas located entirely below the oesophagogastric junction are considered gastric in origin. The use of the ambiguous and often misleading term 'carcinoma of the gastric cardia' is discouraged; depending on their size , these should be called carcinoma of the proximal stomach or carcinoma of the body of the stomach.

Epidemiology

Reliable data on the incidence of tumours of the OG junction are not avali-

Fig. 2.02 Incidence of adenocarcinoma of the stomach (left) compared to adenocarcinoma of the distal oesophagus and oesophagogastric junction (right). Rate per 10,000 hospitalisations from North America.

able at this time. Tumour registries typically distinguish only the adenocarcinoma in Barrett oesophagus and the carcinoma of the cardia.

Adenocarcinomas of the OG junction and 'cardia' share similar epidemiologic characteristics. At both sites, there is a strong predilection for middle-aged and older white males {1133, 2205, 1473}, with a marked increase in incidence in recent years. This is in contrast to the worldwide decline of adenocarcinoma of the gastric body and antrum (Fig. 2.02). Despite the increasing incidence, the cumulative rates at the OG junction and the cardia are still much lower than those observed in the 'non cardia' stomach. In the Norwegian cancer registry data for the period 1991/92 {664}, the age adjusted incidence rate for the combined ade-nocarcinoma of the distal third of the oesophagus and proximal stomach was 3.0 for males and 0.8 for females, while the incidence for all subsites of the stomach was 13.8 in males and 6.5 in females.

Aetiology

The most consistent association described for carcinoma at the OG junction is with gastro-oesophageal reflux. In contrast with the aetiological factors involved in 'non cardia' gastric cancer, there is no consistent association with diet (salty food in excess and lack of fruits and vitamins) nor Helicobacter pylori infection, while in the body and antrum of the stomach, intestinal metaplasia occurs in relation to chronic gastritis due to H. pylori infection {1829, 88, 343}.

Intestinal metaplasia is judged to be the precursor of adenocarcinoma both in the oesophagus and in the stomach {1797}.

However, there appear to be significant differences in the pathogenetic, morphological and histochemical characteristics, as well as in the clinical importance of intestinal metaplasia in the two organs (Fig. 2.03).

In the oesophagus, gastro-oesophageal reflux disease (GERD) is accepted as the cause of intestinal metaplasia (Barrett oesophagus); chronic reflux oesophagitis is a strong risk factor for adenocarcinoma of the oesophagus {1001}. The cancer risk for patients with intestinal metaplasia in the oesophagus appears to be substantially higher than for patients with intestinal metaplasia in the stomach {1797} In contrast to the stomach, infection with H. pyloridoes not appear to play a direct role in the pathogenesis of oesophageal inflammation and metapla-

Oesophagus sia {1381, 1076, 1617, 1889, 501, 1087, 6, 1579}. Indeed, recent reports suggest that gastric infection with H. pylori may actually protect the oesophagus from cancer by preventing the development of reflux oesophagitis and Barrett oesophagus {2090, 998, 2094, 309, 2012, 615, 350, 504, 1948, 2213, 837, 1957}. In biopsies from the SC epithelial junction of patients with Barrett oesophagus, a peculiar hybrid cell type has been observed that has both microvilli (a feature of columnar cells) and intercellular bridges (a feature of squamous cells) on its surface {1740, 1651, 155}. The relationship between intestinal metaplasia in the proximal stomach and in the oesophagus is disputed {1797}. Intestinal metaplasia has been found in the proximal stomach (gastric cardia) of only a minority of patients with Barrett oesophagus {1498}.

Recent studies indicate that specialized intestinal metaplasia at a normal-looking OG junction carries a much lower rate of malignancy than in Barrett oesophagus {715}. Indeed, intestinal metaplasia at the oesophagogastric junction has been found with similar frequencies in Caucasians with GERD (a high risk group for adenocarcinoma at the junction) and in African Americans without GERD (a low risk group) {269}.

Cancers of the gastric cardia resemble oesophageal adenocarcinomas in terms of their association with GERD {1133, 2205, 1473}.

Stomach

GERD H. Pylori

Reflux Oesophagitis Gastritis

Reflux Oesophagitis Gastritis

Intestinal Metaplasia

Intestinal Metaplasia

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Herbal Remedies For Acid Reflux

Herbal Remedies For Acid Reflux

Gastroesophageal reflux disease is the medical term for what we know as acid reflux. Acid reflux occurs when the stomach releases its liquid back into the esophagus, causing inflammation and damage to the esophageal lining. The regurgitated acid most often consists of a few compoundsbr acid, bile, and pepsin.

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