There is a lot of public concern about the man-made chemicals in our food,
environment and household goods. But the evidence linking such chemicals to
cancer has generally been poor or inconsistent.
Concerns have focused on a group of chemicals that could mimic or disrupt
the effects of human hormones, like oestrogen. These chemicals have several
names including 'hormone mimics' and 'endocrine-disrupting chemicals' (EDCs).
EDCs are a diverse group of chemicals and can be found all around us in thing
like plastics, pesticides, fungicides, vehicle exhaust fumes and solvents. So
we can be exposed to them by eating or drinking affected food or water,
absorbing them through our skin, or indeed breathing in EDCs that are in the
air. The worry is that EDCs could disrupt the action of hormones in our bodies,
leading to health problems, including cancer.
Hormone mimics and cancer
Some people suggest that the increasingly common use of EDCs explains why
breast
cancer,
prostate
cancer and
testicular
cancer have become much more common in the last century. But there is no
good direct evidence to support this.
A number of other things are likely to have contributed to the increase in
rates of breast cancer over the last few decades. These include the trend
towards having smaller families later on in life, and the increasing number of
women of women who are
overweight
or obese, or drink
alcohol.
All of these are known risk factors for breast cancer.
There has also been a trend towards more prostate cancers being diagnosed in
men. Much of this is linked to the introduction of
PSA
testing, which has led to some prostate cancers being diagnosed that would
otherwise have gone unnoticed and not caused any harm. More early stage
prostate cancers are also being diagnosed in men who have a
transurethral
resection of the prostate (TURP), an operation that is often used to treat
men with a non-cancerous swelling of their prostate.
Some scientists have suggested that men may have higher risks of testicular
cancer if their mothers were exposed to high levels of EDCs while pregnant. But
this is still just a theory and there is very little direct evidence to support
it. The trends also show that testicular cancer numbers started increasing in
the 1920s. This was long before the large increases in EDC use in the
mid-to-late twentieth century.
We know that hormones are linked to the development of some cancers,
including breast, prostate, testicular and womb cancers. But at the moment
scientists don't fully understand what goes wrong in the body to allow our own
hormones to cause cancer. Without understanding this, it's also hard to explain
how EDCs could cause cancer. Studies with animals and cells have shown that
EDCs can disrupt hormone interactions and cause cancer in the laboratory. So it
is possible that EDCs could cause cancer in people, but we don't know for sure.
Some studies suggest that EDCs from pesticides may be linked to cancer in
people who are exposed to high levels of pesticides as part of their job, such
as farmers or people working in industry.
