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go by many other names including distal oesophageal cancers, proximal gastric cancers and cancers of
cardia. This has led to discrepancies in the literature regarding the classification, pathophysiology, surgical
[4]
approach and prognosis. The most widely accepted definition for GEJ cancer is that proposed by Siewert et al.
and led to the tumours being classified as a distinct entity from gastric or oesophageal cancers. He
proposed that GEJ tumours be classified as those having epicentre of the cancer within 5 cm proximal or
distant to the Z-line. The Union for International Cancer Control (UICC) has adopted a similar definition
and suggests that tumours that extend into the oesophagus classified and staged using an oesophageal
scheme while those without oesophageal extension are staged using the gastric cancer scheme even if
[5]
they occur within 5 cm distant to the GEJ . American Joint Committee on Cancer (AJCC) suggests that
cancers involving the GEJ that have their epicentre within the proximal 2 cm of the cardia (Siewert Type I/
II) are to be staged as oesophageal tumours while those that are more than 2 cm distal to the cardia should
[6]
be staged as gastric cancer .
The importance of accurate and reproducible definition of GEJ cancer is important as the tumour biology,
management is different and importantly the prognosis is considered worse than that of oesophageal and
gastric cancer. Even within GEJ tumours there is marked heterogeneity, Siewert Type II and III are known
[3]
to have better prognosis than Siewert I . GEJ tumours are known to demonstrate aggressive behaviour
with early local invasion and systemic dissemination. As the GEJ tumours borders both the thoracic and
abdominal cavities there is lymph outflow and therefore lymph node metastasis to both these regions.
Moreover, the close relationship of the GEJ cancer to an anatomically complex region bordering multiple
[7]
organs means complete resection can only be achieved by multi-visceral resection .

EPIDEMIOLOGY
GEJ tumour incidence has dramatically increased in Western population and the distal oesophageal cancer
type is the dominant oesophageal cancer type in the USA. Similarly, the rates of proximal gastric cancer
have increased while that of distal gastric cancer has dropped. The rates of GEJ tumours has increased
between 4%-10% every year in USA since 1976 [8-10] . The overall proportion of proximal gastric cancer,
cancer of the cardia and distal oesophageal cancer accounted for about 30%-40% of all gastric carcinoma
in Western countries and interestingly, China, far higher than other Eastern centres such as Japan and
Korea [3,8,9] . However, these numbers have to be taken with a pinch of salt. Historically, the confusion in the
labelling of GEJ tumours with them being previously labelled as oesophageal or gastric cancers or even
“unspecified” under the World Health Organization’s International Classification of Diseases for Oncology
codes could lead to an erroneous result. A study conducted in Sweden revealed that the true incidence
[11]
could be up to 45% higher or 15% lower than reported in its national registry . The secular trend of rising
incidence of GEJ tumours has to be interpreted with caution.

RISK FACTORS
The etiology of GEJ tumours is still unclear. Much of its alarming rise has been blamed on increasing
trends of obesity and GERD. This is likely to explain the rise in Siewert I tumours, which arise from areas
of intestinal metaplasia in the distal oesophagus contributed by chronic GERD due to obesity. However,
it is still unclear if metaplasia is due to acid reflux or bile reflux into oesophagus. Analysis of oesophageal
[12]
fluid in patients with GERD found that they contain 10 times more bile than normal controls .
Animal studies also have shown that duodenal fluid induces Barrett’s oesophagus and oesophageal
adenocarcinoma [13,14] . This might explain why use of acid suppression agents has not lowered the rates of
[1]
GEJ tumours .
Increasing rates of GERD due to acid or bile irritation does not explain the rise in Siewert Type II and III
[15]
tumours. An analysis of GEJ tumours by Siewert et al. found that in contrast to Siewert Type I tumours