From the first moment my wife discovered she
had breast cancer, there was a deafening silence from the men I know. Even ones
whose wives, mothers or girlfriends had breast cancer seemed to have received a
gag order from some Central Cancer Command and did little more than mumble
about the experience. Not one to shut up for any known reason, I started this blog…That
was four years ago – as time passed, people searching for answers stumbled across
my blog and checked out what I had to say. The following entry first appeared in June of 2012...
And now, the original post PLUS AN UPDATE, seven years later...
Doctors harp on
exercise.
Despite the
harping – or in my case, perversely because
of it – I avoid exercise like the plague.
Even so, as I read
more and more sites promoting the “exercise makes you better if you have breast
cancer” meme, I found that almost none of them give any kind of evidence as to
WHY exercise fights cancer and promotes healing.
So I dug into the
sites and finally found some evidence supporting this wild, “Do this one weird
thing…” kind of meme. This week, it’s number:
1)
Increased
levels of pro-inflammatory factors and decreased levels of anti-inflammatory
factors have been linked with increased cancer risk. Physical activity might
reduce systemic inflammation alone or in combination with reduction in body
weight or composition through reducing inflammatory cytokines in adipose
tissue.
What are pro and
anti-inflammatory factors?
Let’s start with
CYTOKINES and let me warn you, even researchers are still a bit fuzzy about
these molecules, which explains the “might” in the paragraph above. We’ll take
this subject as a “details at 11” kind of thing – it’s changing every day, but
TODAY and to the best of our knowledge, we can say that we’re pretty sure that
cytokines are small molecules that are given off by numerous cells and
are used to communicate with each other. Cytokines are a large and diverse
family of molecules with many jobs. One thing we are pretty sure they do to
control the immune system – that collection of white blood cells and chemicals
that spring to work when you’re hurt or sick and the body has to fight off an
infection. The line between cytokines and hormones is also pretty blurry but
PROBABLY, cytokines come from lots of places and there are only set amounts in
the blood – though that amount can leap up during trauma or infection. Hormone
levels are steady. Many cells produce cytokines. Most hormones come from
specific glands (adrenal, pancreas, etc). Also, while usually specific, some
cytokines act like hormones to have an effect on the entire body. Last of all,
some cytokines act outside the immune system and affect the development of the
human body.
As to breast cancer, at least one cytokine affects both the presence of and
severity of breast cancer: “In
a study published in the January 15th issue of Cancer Research…researchers
showed that activation of the CXCR4 [cytokine] receptors [on the cancer cells]
resulted in increased tumor growth and metastasis…and less dependent on
estrogen for continued growth…to become metastatic and resistant to endocrine
therapy…[in] A second study published in the current issue of Surgery…authors
reported that all benign breast tissues had no detectable CXCR4 levels, whereas
all 101 breast cancer patients showed at least some level of this cytokine
receptor. Of these breast cancer patients, 79 had low levels of CXCR4 and
22 had high levels of CXCR4. These high CXCR4 levels were linked with
increased breast cancer recurrence and worse chances of survival…overexpression
of CXCR4 cytokine receptors is linked to worse breast cancer outcomes…blocking
this pathway might become a valuable breast cancer treatment for patients
overexpressing this cytokine receptor.”
The big “might” up
above has given breast cancer, cytokines and exercise a high level of interest.
The third reference below cites a study that, as of my referencing of it, was
still recruiting participants.
So – I’m going to
label THIS particular aspect of exercise and breast cancer as a big MAYBE,
LET’S WAIT AND SEE. So don’t go spreading the word that exercise reduces
cytokines and decreases breast cancer.
Nobody knows
enough yet to say one way or the other.
Update: Not so
fast!
Seven years later,
there seems to be some evidence (in mouse research) that exercise can mitigate
cytokine effects on cancer. I’ve condensed the abstract of the study referenced
below. In essence it says, “Biological aging is associated with progressive
damage accumulation, loss of organ reserves, and systemic inflammation…which
[may lead to] a wide spectrum of chronic diseases, including several types of
cancer. In contrast, aerobic exercise training (AET) reduces inflammation,
lowers all-cause mortality, and enhances both health and lifespan…Lifelong,
voluntary [mice who were trained to regular] wheel-running [experienced much less]
age-related declines in…motor coordination…[and experienced]…partial protection
against sarcopenia, dynapenia, testicular atrophy, and overall organ pathology…chronic
elevation in…cytokines…was…[greatly reduced]…circulating SPARC [a protein in
the body that,] when it accumulates, causes…“tissue fibrosis, nephropathy,
retinopathy, and non-alcoholic fatty liver disease, while [when it’s removed] protects
against the same…”…malignant tumours were also completely absent in [exercising
mice], whereas they were present in the brain (pituitary), liver, spleen, and
intestines of sedentary mice. Collectively, our results indicate that
early-onset, lifelong running dampens inflammaging, protects against multiple
cancer types, and extends healthspan of naturally-aged mice.”
So there you go.
NOT A TREATMENT FOR HUMANS, but evidenced by the newest research.
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