world cancer report - iarc

Fig. 5.73 Drinking the scalding beverage maté is
associated with an increased risk of oesophageal
cancer.
Balloon
mated that 90% of squamous cell carcinomas
are attributable to tobacco and alcohol,
with a multiplicative increase in risk
when individuals are exposed to both factors
[3]. The consumption of scalding hot
beverages, such as maté in South America
(Fig. 5.73), is a risk factor [4], malignancy
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Fig. 5.74 Devices used to collect histological samples
from the oesophagus, used for screening in
Iran.
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being the outcome of chronic mucosal
injury. Other risk factors include consumption
of pickled vegetables, betel
chewing in South East Asia, and oral consumption
of opium by-products in the
Caspian Sea area. Conflicting reports
have proposed a role for human papillomaviruses
in squamous cell carcinoma
[5]. Other environmental risk factors
include nitrosamines, food contamination
with fungi such as Geotrichum candidum
and Fusarium sp. (Food contaminants,
p43) and deficiency of vitamins A and C,
molybdenum, copper and zinc.
Adenocarcinoma of the oesophagus has
been associated with chronic gastrooesophageal
reflux, which most often
underlies repetitive mucosal injury and
predisposes to metaplasia [6]. This
tumour type is directly associated with
Barrett oesophagus, a premalignant
lesion.
Detection
Although endoscopic or cytologic screening
may be useful for early diagnosis in
regions of high incidence, there are no
widely accepted protocols for such interventions.
Cytologic screening of high-risk
asymptomatic populations is carried out
in China with a swallowed balloon
catheter and in Japan with a swallowed
encapsulated brush (Fig. 5.74). Endoscopic
dye-staining with Lugol’s iodine or
toluidine blue aids detection of early
lesions.
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The vast majority of patients initially
complain of progressive dysphagia,
which may not become apparent until
some two-thirds of the lumen has been
obstructed, especially in the case of
squamous cell carcinoma [7]. Regurgitation
and pain on swallowing are frequent,
as is weight loss. Laryngeal nerve
involvement may be indicated by hoarseness.
Patients with adenocarcinomas of
the cardia may also suffer from gastrointestinal
bleeding [8]. A barium swallow
(ingestion of liquid containing barium
prior to X-ray) (Fig. 5.76) may indicate
narrowing or mucosal irregularity, whereas
a chest X-ray may reveal late signs
such as the presence of a mass, tracheal
compression, aspiration pneumonia or
metastases. Endoscopic ultrasonography
is currently the most accurate staging
method, but is not widely available. CT
scanning remains the mainstay of staging
prior to resection, supplemented by
laparoscopy (for lower one-third cancers)
or bronchoscopy (for upper one-third
cancers).
Pathology and genetics
Squamous cell carcinoma (Fig. 5.77)
develops from squamous epithelium
according to a classical dysplasia-carcinoma
sequence (Multistage carcinogenesis,
p84). The most common site of squamous
cell carcinoma is the middle third of
the oesophagus. Microscopically, most
squamous tumours contain islands of
Fig. 5.75 Trends in incidence of oesophageal cancer differ considerably according to geography and reflect differences in prevalence of the two main histological
types. D.M. Parkin et al. (2001) Eur J Cancer, 37 Suppl. 8: S4-66.
224 Human cancers by organ site
Sponge Mesh
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