world cancer report - iarc
world cancer report - iarc
world cancer report - iarc
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OESOPHAGEAL CANCER<br />
SUMMARY<br />
>Cancer of the oesophagus is the sixth<br />
most common <strong>cancer</strong> <strong>world</strong>wide (more<br />
than 400,00 cases per year). Incidence<br />
varies markedly, and is highest in<br />
Western and South Central Asia.<br />
> Squamous cell carcinoma is most common<br />
in developing countries, and is typically<br />
associated with tobacco smoking<br />
and alcohol abuse. Other risk factors<br />
include consumption of very hot beverages<br />
and malnutrition.<br />
> Adenocarcinoma occurs predominantly<br />
in white men from developed countries,<br />
the most important etiological factors<br />
being obesity and chronic gastrooesophageal<br />
reflux.<br />
> Most <strong>cancer</strong>s of the oesophagus are<br />
detected at an advanced stage; five-year<br />
survival rates are less than 15%.<br />
Definition<br />
The great majority of oesophageal <strong>cancer</strong>s<br />
(over 95%) are either squamous cell<br />
carcinomas or adenocarcinomas. Tumours<br />
of the cardia, which arise within the<br />
gastro-oesophageal junction, are sometimes<br />
classified in the same group as<br />
adenocarcinomas of the oesophagus.<br />
Epidemiology<br />
Cancers of the oesophagus are the sixth<br />
most frequent <strong>cancer</strong>s <strong>world</strong>wide. In<br />
2000, the number of deaths due to<br />
oesophageal <strong>cancer</strong> amounted to some<br />
337,500 out of a total of 6.2 million <strong>cancer</strong><br />
deaths <strong>world</strong>wide. About 412,000<br />
cases of <strong>cancer</strong> of the oesophagus occur<br />
each year, of which over 80% are in developing<br />
countries. While squamous cell<br />
carcinoma occurs at high frequency in<br />
many developing countries, adenocarci-<br />
< 1.9 < 3.2<br />
Fig. 5.72 The global burden of oesophageal <strong>cancer</strong> in men. High incidence rates occur in Northern Iran, the<br />
Central Asian republics, North-Central China, parts of South America and in Southern and Eastern Africa.<br />
noma is essentially a tumour of more<br />
developed, industrialized countries.<br />
The differences between incidence of<br />
oesophageal <strong>cancer</strong> in distinct geographical<br />
areas are more extreme than<br />
observed for any other <strong>cancer</strong>. Regions<br />
of high incidence of squamous cell carcinoma<br />
in Asia [1] stretch from the<br />
Turkoman plain in northern Iran through<br />
the central Asian republics to Henan<br />
province in North-Central China, characterized<br />
as the “oesophageal <strong>cancer</strong> belt”<br />
(Fig. 5.72). Incidence rates are as high as<br />
200 per 100,000 and in some areas<br />
there is a female predominance. Other<br />
high-incidence areas are found in parts<br />
of South America and in Southern and<br />
Eastern Africa. Even within these highrisk<br />
areas, there are striking local variations<br />
in risk. Studies of migrant populations<br />
suggest that when they move to<br />
areas of low-risk, they lose their high<br />
rates, confirming the importance of local<br />
environmental factors in causation.<br />
In Europe and the USA, the age-standardized<br />
annual mortality from squa-<br />
< 5.9<br />
< 10.0<br />
Age-standardized incidence/100,000 population<br />
< 38.7<br />
mous cell carcinoma is up to five in<br />
males and one in females per 100,000<br />
population. However, in particular areas,<br />
such as Normandy and Brittany in France<br />
and in the north-east of Italy, the incidence<br />
rates are much higher in males (up<br />
to 30 per 100,000), while remaining relatively<br />
low in females. The incidence of<br />
adenocarcinoma is steadily increasing in<br />
Europe and the USA at a rate of 5-10%<br />
per year. This type of <strong>cancer</strong> now<br />
accounts for more than 50% of all<br />
oesophageal <strong>cancer</strong>s in the USA and in<br />
some European countries [2]. Trends in<br />
incidence of all oesophageal <strong>cancer</strong>s<br />
vary greatly (Fig. 5.75).<br />
Etiology<br />
Consumption of tobacco and alcohol,<br />
associated with low intake of fresh fruit,<br />
vegetables and meat, is causally associated<br />
with squamous cell carcinoma of the<br />
oesophagus <strong>world</strong>wide. However, the relative<br />
contribution of these risk factors<br />
varies from one geographic area to another.<br />
In more developed countries, it is esti-<br />
Oesophageal <strong>cancer</strong><br />
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