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) Physical activity may decrease risk for various cancers by several mechanisms, including decreasing sex hormones
My first reaction to this was, “Huh????”
On second examination and with a little reading, it’s become more obvious.
Most of us know that “Many breast cancers are sensitive to the hormone estrogen. This means that estrogen causes the breast cancer tumor to grow. Such cancers have estrogen receptors on the surface of their cells. They are called estrogen receptor-positive cancer or ER-positive cancer.”
My wife has to take a five year regimen of anastrazole pills that scavenge estrogen from her blood. I wrote about that here: http://breastcancerreaper.blogspot.com/2011/12/next-five-years-anastrazole-whats-it-do.html
But are there OTHER sex hormones that affect the growth of breast cancer tumors and can be lowered with exercise? “Exercise affects hormone production in both females and males. According to the December 2009 issue of "Sports Medicine," exercise suppresses production of luteinizing hormone (LH), follicle stimulating hormone (FSH) and hormones produced by the ovaries. A study published in the June 2010 issue of "Journal of Sports Science and Medicine" indicates physical activity inhibits production of sex steroid hormones including estrogen.
According to recent research, “...LH[RH] agonists [a chemical that binds to a receptor of a cell and triggers a response by that cell...often mimic the action of a naturally occurring substance.]...suppress ovarian function and sex steroid production; the reduction in sex steroids is predicted to lead to the prevention of breast cancer... Ovarian hormones (estrogens and progestogens) are critical factors in the genesis of human breast cancer. During the premenopausal years breast cancer risk increases steeply, but after menopause it increases at a much lower rate. Epidemiologic studies have clearly demonstrated that early menopause...substantially reduces breast cancer risk.”
I covered the effects of estrogen both in the essay linked above and in the first one of this series. What effect does LH and FSH and “hormones produced by the ovaries” have on breast cancer? In a recent study, researchers found that: “the more potent hydroxylated tamoxifen metabolite 4OHNDtam (endoxifen) was the only tamoxifen metabolite positively associated with FSH levels suggesting anti-estrogenic effect on the pituitary. This may explain the observed positive association between a better prognosis and FSH levels during tamoxifen therapy.”
All of this means...WHAT????
Exercise suppresses the production of LH, FSH and “other ovarian hormones” like estrogen and progestogens. At MUCH lower levels, exercise can mimic the effect of the anti-cancer drug, tamoxifen. It does NOT mean “QUIT ALL DRUGS, EXERCISE WILL CURE BREAST CANCER!”!!!!!!! It DOES NOT MEAN “Quit all drugs, exercise will cure breast cancer!”
There IS no miraculous, take-a-pill, jump-on-a-treadmill, move-to-Arizona-and-soak-up-sun cure for breast cancer.
It’s hard. It’s ugly.
A breast cancer survivor needs all the help she can get. Exercise helps.
So, just do it!
References: http://www.livestrong.com/article/476775-hormonal-imbalances-exercise/#ixzz1qhGvuOID, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC138786
Image: https://c2.staticflickr.com/6/5527/10893068965_1d328e8f71_b.jpg
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