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My name is Professor
Diana Eccles and I'm
a professor of cancer genetics
at the University of Southampton
and have a clinical practice in the
Wessex Regional Genetic Service.
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Breast cancer is very
common worldwide,
and the incidence varies quite
markedly between countries.
In Western Europe through to Asia,
as you can see from the graphs
here, mortality is less variable,
and this depends a little bit
on the different
sorts of breast cancer
that occur in these
countries, but also
of course on early
diagnosis and treatment.
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There are many risk factors that
are known for breast cancer,
and increasing age is a very typical
risk factor for breast cancer
and many cancers in
the Western world.
Late age at first birth is
associated with an increased risk
for breast cancer, with a threefold
increase in risk for women
having children after 30
years of age compared to women
having children below
25 years of age.
And of course, women
are having fewer
children in the Western world now.
Excessive iradiation of the
chest in the teenage years
is known to be associated with an
increased risk of breast cancer,
and the evidence from
the Hiroshima bomb
also indicates that
radiation exposure
increases breast cancer risk.
Replacement of oestrogen at the
natural menopause also increases
breast cancer risk, but particularly
if it's given with progesterone.
Oestrogen only seems not to increase
the breast cancer risk significant.
Obesity is clearly a risk for
postmenopausal breast cancer
but less so for
premenopausal breast cancer.
However, in all ages
it increases the risk
of dying from breast cancer.
Early onset of periods and
late menopause also increase
the duration of exposure
to the oestrogen,
and both of those
are risk factors that
increase breast cancer incidence.
And then the main breast cancer risk
factor that we're concentrating on
in this lecture, of course, is a
family history of breast cancer.
But independent of that,
and also very heritable,
is the mammographic density.
