world cancer report - iarc
world cancer report - iarc
world cancer report - iarc
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Certain Possible Uncertain<br />
Age Androgens Body size<br />
High fat diet Race Sexual activity<br />
Family history Estrogens Vasectomy<br />
The distribution of mortality rates is less<br />
affected than incidence by the effects of<br />
early diagnosis of asymptomatic <strong>cancer</strong>s<br />
(whether through screening, or by detection<br />
of latent <strong>cancer</strong> in tissue removed during<br />
prostatectomy operations). Mortality<br />
rates are comparatively high in North<br />
America, Northern and Western Europe,<br />
Australia/New Zealand, parts of South<br />
America (Brazil) and the Caribbean, and in<br />
much of sub-Saharan Africa and low in<br />
Asian populations, and in North Africa (Fig.<br />
5.46). The difference in mortality between<br />
China and the USA is 26-fold (while it is<br />
almost 90-fold for incidence). Racially<br />
based differences are evident within the<br />
United States, where the black population<br />
has the highest incidence (and mortality)<br />
rates, those rates being some 35% higher<br />
250<br />
100<br />
50<br />
25<br />
10<br />
5<br />
2.5<br />
1<br />
Japan<br />
1960197019801990 2000<br />
250<br />
100<br />
50<br />
25<br />
10<br />
5<br />
2.5<br />
1<br />
Selenium Vitamin A<br />
Vitamin E/D Calcium<br />
Phyto-estrogens Lycopene<br />
Table 5.8 Risk and protective (in italics) factors for prostate <strong>cancer</strong>.<br />
Singapore<br />
1960197019801990 2000<br />
than in whites, who in turn have rates considerably<br />
higher than populations of Asian<br />
origin (Chinese, Japanese, Korean).<br />
Etiology<br />
Age is the strongest risk factor for prostate<br />
<strong>cancer</strong>. Development of this malignancy is a<br />
multi-step process associated with a long<br />
natural history [2]. It can be inferred that<br />
the initiation of preneoplastic lesions and<br />
microscopic <strong>cancer</strong> is influenced by environmental<br />
factors which, in turn, implies a<br />
case for lifestyle causes and primary prevention.<br />
Although many of the risk factors for adenocarcinoma<br />
of the prostate (Table 5.8) are<br />
weakly linked, the strong association of<br />
race, familial and geographic patterns with<br />
mortality directs attention to a significant<br />
250<br />
100<br />
50<br />
25<br />
10<br />
5<br />
2.5<br />
1<br />
USA<br />
Black<br />
White<br />
1960197019801990 2000<br />
Australia<br />
role for genetic-environmental interactions<br />
as determining patterns of disease. Dietary<br />
patterns suggest that saturated fat is a significant<br />
risk factor, while micronutrients<br />
such as the vitamins A, E and D, selenium,<br />
lycopene and calcium may exercise a protective<br />
effect against <strong>cancer</strong>.<br />
The role of hormones, especially androgens,<br />
is obviously important, granted the impact<br />
of orchidectomy (excision of the testes) on<br />
progression. However, an endocrine basis<br />
for carcinogenesis is still not well understood.<br />
Genetic polymorphisms in the androgen<br />
receptor may be more important than<br />
any imbalance of hormones in the circulation.<br />
Studies of body size, vasectomy, sexual<br />
activity and cigarette smoking as risk factors<br />
have produced inconclusive, equivocal<br />
results.<br />
A diet characteristic of Asian countries such<br />
as Japan and China, essentially a low fat<br />
intake with consequent low body weight,<br />
with an intake of relatively high levels of<br />
phyto-estrogens (Box: Phyto-estrogens,<br />
p78) may provide the means of restraining<br />
the growth and progression of prostate <strong>cancer</strong>.<br />
A strategy for prevention would be to<br />
increase the intake of phyto-estrogens,<br />
essentially isoflavonoids, lignans and possibly<br />
certain flavonoids [3]. The years of<br />
potential life saved by preventive measures<br />
for prostate <strong>cancer</strong> may be less than for<br />
<strong>cancer</strong>s occurring earlier in life, but the<br />
number of men with the disease <strong>world</strong>wide<br />
adequately justifies a focus on this effort<br />
(Screening for prostate <strong>cancer</strong>, p160).<br />
Fig. 5.46 Trends in prostate <strong>cancer</strong> mortality. Although mortality rates increased generally in the last 30 years, in some places, e.g. the USA, mortality is now<br />
falling. D.M. Parkin et al. (2001) Eur J Cancer, 37 Suppl.8: S4-66.<br />
250<br />
100<br />
50<br />
25<br />
10<br />
5<br />
2.5<br />
1<br />
1960197019801990 2000<br />
250<br />
100<br />
50<br />
25<br />
10<br />
5<br />
2.5<br />
1<br />
Poland<br />
1960197019801990 2000<br />
250<br />
100<br />
50<br />
25<br />
10<br />
5<br />
2.5<br />
1<br />
Spain<br />
1960197019801990 2000<br />
Cancers of the male reproductive tract 209