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The
Lancet
(British Medical Journal) (August, 2003)
Current use of
HRT increased the risk of incident
and fatal
breast cancer. The Million Women study investigated
the effects of specific types of HRT on incidence of
breast cancer in a million UK women. This study showed
the increased incidence is greater for
oestrogen-progestagen
combinations of HRT. This confirms earlier research.
Journal of
American Medical Association (17 July,
2002)
Risks and benefits of
oestrogen plus progesterone hormone replacement therapy in 16,608 healthy post-menopausal
women to assess the long term health benefits and risks
(JAMA. 2002; 288(3):321-333).
The trial was to run
for 10 years but was stopped shortly after 5 years
as the overall health risks exceeded the benefits. Increased risks were seen for
coronary
heart
disease,
breast cancer
and stroke. There was a reduction
in risk for
colorectal cancer,
endometrial cancer and
hip fractures.
As many of these increased risk factors are seen as
reasons for women to be prescribed
HRT, it is expected
that these latest results showing
HRT resulted in not
a prevention but an increased risk for these diseases,
will greatly increase the demand for
natural alternatives
to
HRT.
Journal of
American Medical Association (26 January,
2000)
A study published in the Journal of the American Medical
Association (JAMA. 2000; 283:484-491) has shown that
the
HRT combination of oestrogens with progestins versus
oestrogens alone greatly increases the risk of developing
breast cancer.
This cohort study of
follow-up data from the Breast Cancer Detection Demonstration
Project (BCDDP) from
1980-1995 reanalysed more than 90% of the
world’s
epidemiological data regarding the link between
menopausal HRT and
breast cancer
risk. Results were used from
29 screening centres throughout the United
States, a total of 46,355 postmenopausal
women.
This study found that recent (previous four years),
but not past use, of HRT increased
breast cancer risk
by 8% per year of use. The figures were more pronounced
amongst leaner women (BMI of 24.4kg/m2 or less) who
had an increased risk of
breast cancer with
oestrogen-progestin HRT of 12% per year.
Australian expert on
menopausal health, Professor Sue Davis, director
of research
at Melbourne’s
Jean Hailes Foundation, has challenged the
findings of this study because of
the small number of women
taking the combined oestrogen-progesterone
regime.
National
Cancer
Institute (16 February 2000)
Another US study, published in the Journal of the
National Cancer Institute came to similar conclusions
about the increased risk of using combined HRT.
The case control study concluded that
HRT was associated
with a 10% increased in
breast cancer
risk for each
five years of use. There was a non-significant 6% increase
in breast cancer risk with every five years of use
of oestrogen along, but
the risk with
combined HRT
was substantially higher, at an estimated 24%.
The researchers said
that if the main purpose of adding progesterone to
HRT was
to protect the endometrium, “then
this study would argue that
the adverse effect on the
breast may outweigh the beneficial effect on the endometrium,
at least in terms of
cancer morbidity and mortality”.
U.S. National
Toxicology Program (5th January, 2001)
The U.S. National Toxicology Program is a key United
States medical body. In early 2001 the advisory committee
voted 8-1 to recommend that the hormone, oestrogen,
be listed as a known cancer-causing agent because of
suggested links to
breast and endometrial cancer.
Breast Screening
Australian researchers at the Anti-Cancer Council
of Victoria and Breast Screen Australia have said that
mammography screening for women using
HRT is about
15% less sensitive for detecting
breast tumours, than
it is for women not using HRT. The researchers said
this result was probably because the use of
HRT caused
an increase in the density of breast tissue.
HRT DISCUSSION
Oestrogens are a group
of female hormones essential for the reproductive
process and
the development of
the uterus, breasts, and other physical changes
associated with puberty. Oestrogens
have an effect on about 300
different tissues throughout a women’s body – not
only those involved in the reproductive process,
but also tissues in the central nervous system
(including the brain), the bones, the liver, and the
urinary tract.
Oestrogens determine the characteristic female
distribution of body fat on the hips and
thighs that
develop during
adolescence.
The high
oestrogen
levels that occur during the reproductive years derive
from the
ovaries that produce two major
female hormones, oestrogen and
progesterone.
Other tissues, such as body fat,
skin and muscle can also
form some oestrogen. After
menopause some
amounts of oestrogen continue to
be manufactured in body fat.
The total oestrogen produced after menopause,
however, is far less than that produced
during a woman’s
reproductive years.
Women currently can
expect to live 30 or 40 years of their life in a
postmenopausal
state.
The lower
amount of oestrogen during these decades
puts them at greater risk for
cardiovascular
disease, osteoporosis,
and possibly even Alzheimer’s disease.
Using
Hormone Replacement
Therapy (HRT) to
relieve menopausal symptoms was
becoming
popular as early as
the 1960s. Widespread interest in HRT was
likely spurred by the 1966 publication
of gynaecologist Robert Wilson’s
book Feminine Forever. In his book Wilson glorified
oestrogen as a proverbial “fountain of youth”.
By the mid 1970s American physicians were
writing more than 30 million prescriptions
a year for the hormone,
and approximately half of all menopausal
women were using HRT for a median duration
of five years.
By the early 1980s research had identified long-term
HRT as a way to prevent and manage postmenopausal osteoporosis
(loss of bone density) and as a possible measure in
treating
postmenopausal urinary incontinence. Other
studies done in that decade linked continued oestrogen
use to improvements in cholesterol levels and to a
lower incidence of fatal
heart disease. However there
are a number of other considerations that women should
discuss with their healthcare professional about
HRT,
particularly if they have pre-existing health conditions.
Obtaining specific health benefits depends on the
type of hormone therapy selected:
1.
Oestrogen replacement therapy (ERT) uses oestrogen
alone, called unopposed oestrogen, to combat diseases
related to oestrogen loss, particularly heart disease
and osteoporosis. Unfortunately ERT significantly increases
the risk for
endometrial (uterine) cancer.
2.
Hormone Replacement Therapy (HRT) combines oestrogen
with natural progesterone or its synthetic version,
called progestin, which offsets the risk of
uterine
cancer. The latest research shows that
the long-term
(more than 2 years) continuous use of progesterone
(alone or in combination with oestrogen) is linked
with an increased incidence of
breast cancer
and
heart
disease.
Only about 25 percent
of menopausal women undergo
HRT. Women who reject
HRT may be wary
of the “medicalisation
of menopause” or may dislike
HRT’s possible
side effects, among them breast tenderness,
headaches, and resumed periods. But it is the fear of
breast cancer
that dissuades most women and their health
care professionals from choosing HRT. |
