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Beverly J. Roseberry, MD, reviews different lifestyle changes that can help reduce the risk of breast cancer.
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Family Medicine & Primary Care Specialty
General Surgery Specialty
Internal Medicine Specialty
Plastic & Reconstructive Surgery Specialty
Adult Primary Care Subspecialty
Breast Surgery Subspecialty
Hematology & Oncology Subspecialty
Mayo Clinic
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Past Notes
So I'm excited to talk about this
topic because it's estimated
that 30 to 50%
of breast cancer could be prevented
with certain lifestyle practices.
All right. So we're
going to look at the following five
areas to see
how these areas increase or
decrease risk.
But first, we're going to look at
a simplified mechanism for the
development of breast cancer,
which occurs when DNA damage
occurs to the cell and then
the cells they multiply,
divide and then invade.
The following five factors directly
contribute to the cellular changes
that can lead to breast cancer,
chronic inflammation and
pro-inflammatory pro-inflammatory
cytokines, including insulin
like growth factor interleukin
one and tumor necrosis
factor cytokine
cell and kind mean
signals.
So these are proteins that signal
the cell to divide and
then turn on the inflammatory
process.
Other factors that contribute are
free radicals, estrogen,
acetaldehyde and excess insulin.
However, these factors are
directly influenced by alcohol
use.
Weight and diet.
So first, we're going to look at
specific dietary patterns.
The World Cancer Research Fund, they
analyze global research
on cancer and prevention and
specifically for breast cancer.
They issue a very extensive
report. So I'm going to talk about
their key findings, along with the
American Cancer Society, key
findings
with regards to low fat diets.
They stated that there was limited
evidence and had no conclusion.
However, recent long term follow
up on the Women's Health Initiative,
a randomized clinical trial
found that women who were
assigned to the low fat diet
had a decreased risk for estrogen
receptor positive progesterone
receptor negative breast cancer.
And furthermore, if they later
developed breast cancer, they had
a decrease in mortality from breast
cancer by 21%.
In this group, no more than 24%
of their daily calories came from
fat.
And they also had increased
consumption of fruits, vegetables,
whole grains and also
some modest weight loss.
Furthermore, women's intervention
in nutrition randomized clinical
trial found that women with early
stage breast cancer randomized
to low fat dietary group,
had a 24% higher
five year relapse free
rate.
The Epic study, which is a large
European cohort cohort
study, that an increased
risk for estrogen receptor positive
progesterone receptor positive
breast cancers with diets high
in total and saturated fats.
There's two mechanisms by which
dietary fats elevate risk.
One is that they increase insulin
and interleukin one, and this
leads to cell proliferation.
The second is through the elevation
and estrogen levels, which occur
through the cholesterol pathway
as cholesterol is a precursor
to estrogen.
The American Heart Association
recommends no more than 5% of
daily calories from saturated fats.
So for a 2000 calorie diet,
this is going to be around ten grams
daily.
The Mediterranean diet is high in
consumption of plant based foods.
Low consumption of bread, meat,
poultry and dairy uses extra virgin
olive oil as the main dietary fat
and red wine in moderation.
The World Cancer Research Fund found
insufficient evidence to draw a
conclusion, and several large
systematic reviews still concluded
that evidence is limited.
This is probably related to the
alcohol component, which we'll talk
more about.
However, the American Cancer Society
states that the Mediterranean diet
lowers risk.
Their statement was partly based
on this randomized clinical trial.
The primary outcome of this trial
was cardiovascular disease, and
breast cancer was a secondary
outcome.
So they had about 4300 women
and they were assigned to a
mediterranean diet, supplemented
with extra virgin olive oil.
Mediterranean diet supplemented with
nuts.
In the control group, they found
that the Mediterranean diet,
supplemented with extra virgin olive
oil, had a 62%
lower relative risk compared
to the control group.
Further analysis of the
Mediterranean diet by
looking at alcohol use
subtype of breast cancer and
then a possible status also
found decreased risk.
Specifically, the epic study found
that a mediterranean diet without
alcohol decreased risk for
postmenopausal breast cancer
and the Netherlands cohort study
also found the same result.
The World Cancer Research Fund
concludes that consumption of
alcohol is a convincing cause of
postmenopausal breast cancer and
probably a cause of pre-menopausal
breast cancer.
An observational study done on
88,000 women concluded that
breast cancer is the most frequent
cancer associated with alcohol.
Epic's study estimated that 5%
of breast cancers could be caused by
alcohol alone, and this would be
about 14,000 cases yearly.
Just 5 to 10 grams per day has
been estimated to increase risk by
5 to 9%.
This is problematic because there's
14 grams of alcohol in one standard
drink, so there's five grams
of alcohol and just 1.8
ounces of wine.
So why does alcohol have such a
significant effect?
Well, alcohol it's also metabolized
in the breast tissue.
It's the byproduct of alcohol,
the acetaldehyde, that causes so
much damage.
The breast tissue has
abundance amounts of alcohol,
dehydrogenase, but it
doesn't have a lot of aldehyde
dehydrogenase.
Furthermore, the amount of the
alcohol dehydrogenase
can vary based on
specific genetics.
There is a specific variant
that can lead to 2.5
times the amount of acetaldehyde
produced.
So in the breast tissue.
Furthermore, it has limited
limited amounts of the aldehyde
dehydrogenase.
So you can see that some women are
just simply going to be more
susceptible to the damaging effects
of alcohol.
The Acetaldehyde directly damages
DNA and it blocks folate,
which is necessary for DNA repair.
It damages tumor suppressor genes
and increases the amount of
aromatase, which increases the
production of estrogen.
And furthermore, it inhibits enzymes
that degrade estrogen.
So if just 1.8 ounces
of wine daily can
elevate risk, one can see why
no safe threshold has been
identified.
In the American Cancer Society
recommends avoiding alcohol
altogether.
Now I'm going to transition over to
specific food groups
with regards to total fruits and
vegetables.
The World Cancer Research Fund and
the American Cancer Society states
evidence is limited but suggestive
for reduction of estrogen receptor
negative breast cancers, with high
consumption of non-starchy
vegetables and foods containing
carotenoids.
Three large systemic reviews
continue to support this.
It's the polyphenols, the
carotenoids, and the flavonoids
that reduce the risk.
These counteract oxidative
stress, inhibit those inflammatory
cytokines, decrease estrogen
levels, eliminate free radicals,
repair DNA and inhibit cell
proliferation.
You should aim for about five a day,
and this is a really basic slide,
but it highlights that one.
Serving really isn't that much.
So eight strawberries,
half of an apple, 12 baby carrots
with regards to red and processed
meat. The World Cancer Research
Fund concludes that evidence is
limited.
But the American Cancer Society
states that diets low in
animal fat reduce
risk.
Other studies show a strong
correlation with high consumption
due to the elevated levels of poly
and means the carcinogens
created through cooking, the
estrogen given to animals,
and also elevates levels
of insulin like growth factor.
So the recommendations are no more
than three servings a week of red
meat and minimal to no
processed meats.
Calcium rich, low fat dairy
may reduce risk.
However, evidence suggests that low
fat dairy, but not milk,
reduces the risk.
And the evidence is seen more for
premenopausal women.
In addition, foods
that are high in calcium may also
decreased risk, with a meta analysis
showing intake of 300 milligrams
of calcium daily, do you see
decreasing risk by 13%
for premenopausal women and 4%
for postmenopausal?
And this with the calcium, it's not
calcium supplements, it's the
calcium that comes from the food.
There was concern in the past that
soy products might elevate
risk. The World Cancer Research Fund
has no conclusion on this,
but a 2019 literature
review of three meta analysis
show an inverse relationship
and a 2020 review also show
a protective role.
The protective role was higher in
post-menopausal Asian woman.
And this probably has to do with the
consumption of isoflavones
as their diet contained about
45 milligrams of isoflavones
compared to 3.2
milligrams daily in the western
diet.
Isoflavones are phyto estrogens
and they bind to the sugar
receptors.
But there are two types of estrogen
receptors alpha and beta
and the phytoestrogens bind to the
beta receptors blocking the
proliferative action of the alpha
receptors.
The types of soy consumed should be
whole or fermented
and process soy or supplement.
Also, proteins and isoflavones
isolates should be avoided.
30 grams daily of soy, which
contain 10 to 20 milligrams of
soy isoflavones may be beneficial.
With regards to fiber.
The World Cancer Research Fund said
evidence is limited.
It had no conclusion, but systemic
review showed decreased risk with
high fiber diets.
This may be due to the decreasing
circulating levels of estrogens.
Fibers. A good source of
phytoestrogens and fiber also
decreases cholesterol.
So a high fiber diet, which would be
about 30 grams daily, may be
beneficial
with exercise and breast cancer.
The World Cancer Research Fund
concludes that vigorous physical
activity probably protects
against pre and postmenopausal
breast cancer.
And the American Cancer Society
concludes there's an estimated
risk reduction of up to 25%,
with moderate to vigorous exercise,
which decreases insulin levels,
decreases estrogen in postmenopausal
women, and helps maintain a healthy
body weight.
If you are exercising
150 minutes to 300
minutes of moderate intensity are 75
to 150 minutes of vigorous,
intense activity weekly that you're
meeting the current recommendations.
That's just 0.02%
of your waking hours.
We're still working out the optimal
duration and type of exercise,
but it looks like 300 minutes
or more is ideal.
And there's an estimate an
additional 3% risk reduction
for every additional 180 minutes
of moderate exercise weekly
in addition to recreational
exercise.
Physical activity also matters.
Studies that looked at physically
active women found
a lower risk of breast cancer
compared to women who were not
physically active.
I don't know if everybody remembers
this from physics.
A body in motion stays in motion,
but this is still true.
Breast cancer patients who watch 3
to 5 hours per week had a 27%
reduction in mortality.
There's overwhelming evidence that
being overweight or obese
increases the risk of breast
cancer.
Breast cancer is one of 13
cancers that is associated with
obesity.
The World Cancer Research Fund
concludes that being overweight or
obese throughout adulthood increases
the risk of postmenopausal breast
cancer.
Counterintuitively, they also
concluded that being overweight
between the ages of 18 and 30
probably protects against
pre-menopausal and postmenopausal
breast cancer.
This statement is by no means a
recommendation to be overweight
in early adulthood, and
we don't understand the mechanism
behind this.
Some of the thoughts are that it
might have to do with women in this
group have early differentiation
of the breast tissue, which may
render it less susceptible to
cancer.
Data from the Women's Health
Initiative showed that
postmenopausal women with a BMI
greater than 35 had a 58%
increased risk for estrogen receptor
positive progesterone receptor
positive breast cancer compared
to women with a BMI.
Less than 25
woman with normal BMI, who gained
greater than 5% body weight
had elevated risk compared to women
with stable weight.
Extra facts stored in the body as
adipose tissue.
This tissue functions as an
endocrine organ that produces many
different types of hormones that
lead to chronic inflammation and
excess insulin.
Excess body weight increases
estrogen levels through the
production of leptin.
The ADIPOCYTE produces leptin,
which increases level of aromatase,
which then leads to increased levels
of estrogen.
Obesity has also been shown to
increase mortality, and a met
analysis show that women who are
obese when diagnosed had
a 33% increase in mortality.
Another meta analysis found that
women with a BMI greater than 30
at diagnosis had overall decreased
survival.
This may be partly due to
chemotherapy being less effective,
even when it is dosed for body
weight in some studies also
show that aromatase inhibitors are
also less effective.
However, weight loss has been shown
to significantly reduce risk,
as seen by this study that looked at
180,000 postmenopausal
women.
They found that with just as little
as £4.4 of
weight loss, that could decrease
risk by 13%.
Furthermore, £20 of weight loss
decreased risk by 26%.
So what can we tell women
who say, well, I've lived a healthy
lifestyle and then they're diagnosed
with breast cancer.
Women at a healthy weight when
diagnosed respond better to
treatment.
Women's Health Initiative long term
follow up showed that women
who had followed low fat diets and
were later diagnosed had decreased
mortality of 21% from
breast cancer.
The Women's Intervention and
Nutrition Study found a 24%
decrease in mortality for women with
early stage breast cancer assigned
to a low fat diet.
Furthermore, walking 3 to 5 hours
per week was associated with a 27%
decrease in mortality.
So we can tell these women that it
was beneficial and that they should
continue to engage in these healthy
lifestyle practices.
And furthermore, for women who are
diagnosed and haven't yet adopted
these healthy lifestyle patterns,
it's not too late to start.
Thank you.
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