world cancer report - iarc

BLADDER CANCER
SUMMARY
> Bladder cancer is the ninth most common
cancer worldwide, with 330,000
new cases and more than 130,000
deaths per year.
>Bladder cancer is primarily attributable
to smoking, which accounts for 65% of
male and 30% of female cases in some
developed countries. Other less important
causes include analgesic abuse
(phenacetin), some types of cancer
chemotherapy and, historically, occupational
exposure to chemicals such as 2naphthylamine.
In Egypt and some Asian
regions, chronic cystitis caused by
Schistosoma haematodium infection is
a major risk factor.
> Treatment based on endoscopy, surgery,
radiotherapy and cytotoxic drugs often
permits long-term survival in developed
countries, where 65% of patients live for
at least five years after diagnosis.
Definition
More than 90% of bladder cancers are
transitional cell carcinomas. Much less
common are adenocarcinoma (6%), squamous
cell carcinoma (2%) and small cell
carcinoma (less than 1%).
Epidemiology
Bladder cancer accounts for approximately
two-thirds of all urinary tract cancers. By
incidence, bladder cancer is the ninth most
common cancer worldwide, although in the
USA, for example, bladder cancer is the
fourth most frequent tumour among men.
Approximately 336,000 new cases
occurred in 2000, two-thirds of which were
in developed countries [1]. Incidence and
mortality rise sharply with age and about
two-thirds of cases occur in people over the
age of 65. The male:female ratio is approximately
3:1. High incidence rates (>12 per
100,000 men and >3 per 100,000 women)
228 Human cancers by organ site
< 3.2
< 5.3
Fig. 5.81 The global incidence of bladder cancer in men. Although the majority of cases occur in developed
countries, bladder cancer also occurs at high rates in some developing countries, including parts
of Northern Africa and South America.
are observed throughout Southern,
Western and Northern Europe, North
America, Australia, Western Asia, Northern
Africa and Uruguay (Fig. 5.81) Bladder cancer
incidence is either rising moderately or
is steady in most developed countries.
About 132,000 people each year die from
bladder cancer, men throughout the world
having a mortality rate of 10 per 100,000
population, and women 2.4, although these
values nearly double for developed countries.
Etiology
The most important risk factor for bladder
cancer is cigarette smoking, which
accounts for approximately 65% of male
cases and 30% of female cases in populations
of developed countries [2]. It is likely
that smokers of black (air-cured) tobacco
are at a greater risk than smokers of
blond (flue-cured) tobacco and this may
explain some of the disparity observed in
European incidence rates and also the
high incidence observed in Uruguay. The
< 9.2
< 15.5
Age-standardized incidence/100,000 population
< 45.3
risk associated with tobacco smoking, and
in particular with black tobacco smoking,
is likely to be due to the presence in the
smoke of aromatic amines including benzidine,
4-aminobiphenyl, 2-naphthylamine
and 4-chloro-ortho-toluidine. Bladder cancer
risk increases approximately linearly
with duration of smoking, reaching a fivefold
risk after 40 years (Fig. 5.82). The risk
also increases with the number of cigarettes
smoked, up to approximately 20
cigarettes per day; above that level, no further
increase in risk is observed. Upon
smoking cessation, a substantial decrease
in risk of bladder cancer is observed within
several years, implying an effect in late
stages of the carcinogenic process.
Work in the rubber and dyestuff industries
and specifically occupational exposure to
aromatic amines, particularly including 2naphthylamine
and benzidine, are correlated
with a high risk of bladder cancer [3].
Exposure to polycyclic aromatic hydrocarbons,
polychlorinated biphenyls, formaldehyde,
asbestos and solvents, and work in